JPH09223460A - Exposing apparatus for color picture tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide sufficient illuminance and easily control the illuminance distribution in an exposing apparatus. SOLUTION: An exposing apparatus has a supporting part 13 to position and support a panel 1, a light source apparatus 14 is installed in a lower part of the supporting part 13, and a lens optical system 17 and a light quantity correcting filter 18 are arranged. The light source apparatus has a light source lamp 15 comprising an ultra high pressure mercury lamp in the inside and a cover glass 30 is installed in an upper part of the light source lamp. The cover glass 30 is projected toward both of the light source lamp side and a panel side and in a relation of the curvature calculated by averaging the curvature in each axial direction corresponding to each axis of the panel 1, the curvature on the panel side is larger than the curvature on the light source side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure device for forming a fluorescent screen of a color picture tube, and more particularly to a shape of a cover glass provided on an upper part of a light source device.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 5, a color picture tube has an envelope having a substantially rectangular panel 1 and a funnel 2 integrally joined to the panel 1. A phosphor screen 3 formed of a phosphor layer of three colors emitting blue, green and red is formed on the inner surface, and a shadow mask having a large number of electron beam passage holes formed inside the panel 1 facing the phosphor screen 3. 4 are arranged. On the other hand, in the neck 5 of the funnel 2, an electron gun 7 that emits the three electron beams 6 is arranged. Then, the electron beam 6 emitted from the electron gun 7 is deflected by a magnetic field generated by a deflecting device 8 mounted outside the funnel 2, and the fluorescent screen 3 is horizontally and vertically scanned to display a color image. Is configured to.

As the fluorescent screen 3 of such a color picture tube, there are a fluorescent screen 3 in which three color phosphor layers are formed in a dot shape and a fluorescent surface in a stripe shape. As an example of the dot-shaped phosphor screen, as shown in FIG. 6, one formed of three-color phosphor dots 10B, 10G, 10R in a predetermined array, or as shown in FIG. Three-color phosphor dots 10B, 10 are provided in the holes of the light absorption layer 11.
Some are formed so that G and 10R are embedded.

The fluorescent screen of such a color picture tube is conventionally formed by a photographic printing method. For example, the phosphor screen having the matrix-shaped light absorption layer 11 shown in FIG. 7 will be described. First, polyvinyl alcohol (PVA) and ammonium dichromate (AD) are formed on the inner surface of the panel.
Forming a photosensitive film by applying a photosensitizer containing C) as a main component,
This photosensitive film is exposed through a shadow mask, and a pattern corresponding to the electron beam passage hole of the shadow mask is printed on the photosensitive film. Next, the photosensitive film having a pattern corresponding to the electron beam passage hole is developed to remove the unexposed portion and form a dot-shaped resist film. Next, a black light absorbing paint is applied to the inner surface of the panel on which the resist film is formed to form a light absorbing paint layer, and the light absorbing paint on the resist film is removed together with the resist film to remove the light from the panel. A matrix-shaped light absorbing layer is formed on the inner surface with the removed portion of the resist film as a gap.

Thereafter, a phosphor slurry containing PVA, ADC and a phosphor of any one color, for example, a phosphor containing a blue phosphor as a main component, is applied to the inner surface of the panel having the light absorbing layer to form a phosphor slurry layer. The phosphor slurry layer is exposed through a shadow mask, and a pattern corresponding to the electron beam passage hole of the shadow mask is printed on the phosphor slurry layer. Thereafter, the phosphor slurry layer having a pattern corresponding to the electron beam passage hole is developed to remove the unexposed portion, and the dot-shaped phosphor layer 10B is formed in the gap portion of the light absorption layer. By repeating this method of forming the phosphor layer 10B for the three-color phosphor, the three-color phosphor layers 10B, 10G, and 10R are formed in the gap portion of the light absorption layer.

Further, the phosphor screen having no light absorption layer shown in FIG. 6 is formed by repeating the steps of forming the phosphor layer. By the way, in the above-described phosphor screen forming method, when a pattern corresponding to the electron beam passage hole of the shadow mask is printed on the phosphor screen forming member layer such as the photosensitive film or the phosphor slurry layer formed on the inner surface of the panel, FIG. The exposure apparatus shown in is used. This exposure apparatus has a supporting portion 13 for positioning and supporting the panel 1, and a light source device 14 is arranged below the supporting portion 13. The trajectory of the light beam 16 emitted from the light source lamp 15 of the light source device 14 in the direction of the panel 1 positioned and supported by the support portion 13 from the light source device 14 is the trajectory of the electron beam emitted from the electron gun of the color picture tube. An optical lens system 17 including a correction lens and the like, a light intensity correction filter 18 for adjusting the illuminance distribution on the phosphor screen forming member layer 15 on the inner surface of the panel, that is, the exposure light amount for each part of the phosphor screen forming member layer 15 are arranged. Has been done.

The correction lens is usually an aspherical lens having a smooth continuous curved surface. Further, the light amount correction filter 18 is formed by depositing a metal vapor deposition film of Ni, Cr or the like on a transparent glass substrate so that the film pressure is thicker in the central portion and thinner in the peripheral portion so that the central transmittance is higher than that in the peripheral portion. The transmittance distribution curve is set to be low. This is because the illuminance of the peripheral portion sharply drops with respect to the illuminance of the central portion of the inner surface of the panel, and the distribution of the light transmittance of the shadow mask must be taken into consideration in the actual exposure.

Here, the light source device 14 is, as shown in FIG. 9, a linear light source 20 composed of a straight tube type super high pressure mercury lamp 15.
A light-shielding slit blade 21 is attached to the upper part of the so that the light emitted from the linear light source 20 is regulated by the slit width. Further, the lamp house 21 is housed in a lamp house 21 having a cover glass on the upper part so that necessary energization and cooling can be performed.

[0009]

However, the shape of the inner surface of the panel of the recent color picture tube is not a single spherical surface as in the prior art, but is a curved surface expressed by a higher-order formula and tends to be flat. On the other hand, the electron beam passage holes of the shadow mask often have a pitch change more than those having a constant pitch, and the fine pitch is progressing in response to the high definition of the color picture tube. Correspondingly, there are various requirements for the transmittance distribution of correction filters used in exposure equipment, such as concentric circles, ellipses, and asymmetric distributions on each axis, and there are demands for multiple types of light quantity correction filters with improved accuracy. There is.

When such a light amount correction filter is formed of a metal vapor deposition film as in the conventional case, it is difficult to make the transmittance distribution into a desired distribution. Furthermore, when such a light amount correction filter is applied to the manufacture of a color picture tube in which the inner surface of the panel is flat and the deflection angle is large, even a slight change in the light source position causes uneven illumination distribution and uneven exposure. It will be easier. This exposure unevenness changes the size of the gaps in the matrix- or stripe-shaped light absorbing layer or the size of the dot-shaped or stripe-shaped three-color phosphor layer, and deteriorates the image quality, especially white uniformity. In a remarkable case, the appearance quality is also deteriorated. In addition, defects such as chipping and dropping of the three-color phosphor layer occur in the phosphor screen forming step, which also causes a decrease in yield.

On the other hand, with the increase in the size of the screen, the shortage of the light amount around the panel, especially near the diagonal, has become a problem.
For example, when a dot-shaped black matrix is to be formed, there is a problem that the hole diameter in the peripheral portion becomes smaller than that in the central portion of the panel. Such a difference in hole diameter between the central portion and the peripheral portion of the panel causes image deterioration such as imbalance between resolution and brightness.

There are methods such as changing the slit width of the light source device and providing a reflection film on the light source lamp in order to obtain the absolute light amount near the diagonal of the screen, but this is not sufficient yet and the absolute light amount is insufficient. In addition, the illuminance at the vertical edge becomes too large compared to the illuminance at the horizontal edge and the diagonal edge of the screen, and the illuminance correction filter cannot completely correct the illuminance.

As described above, an object of the present invention is to provide an exposure apparatus for a color picture tube which can secure a sufficient illuminance in the exposure apparatus and can easily control the illuminance distribution in each axial direction of the screen. And

[0014]

In view of the above problems, the present invention provides a support portion for positioning and supporting a panel having a phosphor screen forming member layer formed on its inner surface, and an inner surface of the panel positioned and supported by this support portion. A light source device having a light source lamp for exposing the phosphor screen forming member layer on the inside and a cover glass provided on the upper surface of the panel side, and an exposure device for a color picture tube, wherein the cover glass of the light source device is a light source. It is characterized in that it is convex toward both the side and the panel side, and further that the average curvature of the panel side curved surface is larger than the average curvature of the light source side curved surface.

Further, a support portion for positioning and supporting the panel having the phosphor screen forming member layer formed on the inner surface thereof, and a light source lamp for exposing the phosphor screen forming member layer on the inner surface of the panel positioned and supported by the support portion are provided inside. A light source device having a cover glass on the upper surface of the panel side, and an exposure device for a color picture tube, the cover glass of the light source device is convex toward both the light source side and the panel side. It has a curved surface, and the amount of depression from the center of the panel-side curved surface to the position corresponding to each axial end of the panel is in the order of the diagonal axis, the horizontal axis, and the vertical axis.

By making the shape of the cover glass of the light source device convex toward the light source side, it is possible to use a light flux in a range not used by the plate-shaped cover glass for exposure, and improve the exposure illuminance. it can. Then, the panel side of the cover glass is also made convex so that the illuminance balance in each direction can be corrected.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described based on embodiments with reference to the drawings. FIG. 1 shows an exposure apparatus according to the embodiment. This exposure apparatus has a supporting portion 13 for positioning and supporting the panel 1, and a light source device 14 is arranged below the supporting portion 13, and the light source device 14 is positioned and supported by the supporting portion 13 in the direction of the panel 1. , A lens optical system including a correction lens that sequentially approximates the trajectory of the light emitted from the light source device 14 to the panel 1 positioned and supported by the support portion 13 to the trajectory of the electron beam emitted from the electron gun of the color picture tube. 17 and a light amount correction filter 18 for correcting the exposure light amount to each part of the phosphor screen forming member layer 12 such as a photosensitizer layer or a phosphor slurry layer formed on the inner surface of the panel 1 positioned and supported by the supporting portion 13 Has been done. In FIG. 1, reference numeral 4 is a shadow mask attached to the panel 1.

The light source device 14 is provided with a light source lamp 15 composed of an ultra-high pressure mercury lamp inside, and a cover glass 30 is provided on the upper part of the light source lamp. The configuration is the same as that shown in FIG. 9 except the shape of the cover glass 30. As shown in FIG. 2, the cover glass 30 is convex toward both the light source lamp 15 side and the panel 1 side, and the curvature relationship obtained by averaging the curvatures in the respective axial directions corresponding to the axes of the panel is the light source side. The curvature on the panel side is smaller than the curvature of. Further, the light source lamp is arranged within the focal length of the cover glass. Furthermore, when considering the cross-sectional shape, the light converges toward a region thicker than the place where the plate thickness is thin, so in order to balance the amount of light to be converged to a predetermined balance, the plate thickness corresponding to each axial direction of the panel Are in control.

Next, the improvement of the illuminance of the exposure light quantity and the control of the illuminance distribution by the shape of the cover glass 30 will be described with reference to the drawings. FIG. 3 is a diagram for explaining the illuminance improving mechanism by comparing the shape of the cover glass in the conventional exposure apparatus with the shape of the cover glass according to the present invention, and the line indicated by the arrow represents the light ray from the light source. FIG. 3 (a)
Compared with the conventional cover glass shape as shown in FIG.
By making the light source lamp side convex as shown in (b), it becomes possible to utilize the light flux that could not be used in the conventional cover glass for the exposure, so that the exposure illuminance can be improved. .

By arranging the light source lamp close to the cover glass within the focal length on the light source side, the light emitted from the light source lamp can be used in a wider range, and a large exposure illuminance can be secured. .

A quarter quadrant of the shape of the cover glass 30 on the panel side is cut out and shown in FIG. this is,
With the tube axis as the Z axis, the horizontal direction of the panel as the X axis, and the vertical direction as the Y axis, the shape at the position on the cover glass corresponding to each axial end of the screen is shown.

Positions P on the X-axis, Y-axis and Z-axis shown in FIG.
₁ , ₁ , P ₂ , and P ₃ are positions where the exposure light rays for exposing the horizontal edge, the vertical edge, and the diagonal portion of the inner surface of the panel pass, respectively. Then, the center sagging amount Z ₁ from the O to the position _{P 1, P 2, P 3} , Z 2, Z 3 has a small Z _3, Z _1, Z
It is increasing in order of ₂ . Thus, if the amount of dip on the upper surface is diagonal, horizontal, and vertical axes in order, considering the cross-sectional shape of only the panel side, the shape of the cover glass through which the light rays that expose the periphery pass is the vertical axis end. , The thickness increases from each of the horizontal axes toward the end of the diagonal axis, and the thickness of the vertical axis becomes the minimum. Since the exposure light beam tends to converge on the thick plate portion, it becomes possible to correct the amount of light at the vertical axis end, which has been a problem in the past, to the horizontal axis end and the diagonal axis end. As a result, the illuminance distribution of the exposure light beam can be smoothed before reaching the light amount correction filter, and the transmittance distribution of the light amount correction filter can be easily controlled.

Since the light source lamp is arranged in the light source device, the curvature of the cover glass on the light source side cannot be increased so much in order to maintain the cooling efficiency of the light source lamp. Therefore, the curved surface shape on the panel side is also made convex so as to have a lens effect, and the illuminance distribution is controlled by the plate thickness distribution. That is, the panel side is larger than the light source side as the average curvature obtained by averaging the curvatures in the respective axial directions.

As described above, by devising the shape of the cover glass of the light source device, the light from the light source is efficiently converged to improve the illuminance, and the converged light is diverged in a predetermined balance in each axial direction. By doing so, the illuminance balance is controlled.

Since the exposure illuminance distribution can be smoothed before the exposure light beam reaches the light quantity correction filter, the requirement for the light quantity correction filter can be relaxed. Therefore, the light quantity correction filter can be easily created, and a stable fluorescent screen can be created.

In addition, although the cover glass of the present invention tends to increase the thickness of the glass, the reduction rate of transmitted illuminance can be suppressed to 8%, which is about the same as that of the conventional cover glass. No problem.

[0027]

As described above, according to the present invention,
It is possible to control the illuminance distribution by making both sides of the cover glass convex so as to have a lens function and devising the shape. Therefore, the requirement for the transmittance distribution for the illuminance correction of the light amount correction filter can be relaxed, and the fluorescent screen can be stably created.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a shape of a cover glass of the light source device in FIG.

FIG. 3 is a diagram showing the action of the shape of the cover glass on the light source side, FIG. 3 (a) shows a flat cover glass as a conventional cover glass, and FIG. 3 (b) shows the present embodiment. A cover glass is shown.

FIG. 4 is a schematic view showing a shape of the cover glass on the panel side of the cover glass, which is cut out by a quarter.

FIG. 5 is a cross-sectional view showing a configuration of a color picture tube.

6A and 6B are diagrams showing a structure of a phosphor screen composed of phosphor dots, FIG. 6A is a schematic plan view, and FIG. 6B is a sectional view thereof.

FIG. 7 is a diagram showing a structure of a phosphor screen composed of a matrix-shaped light absorption layer and phosphor dots, and FIG.
Is a schematic plan view, and FIG. 6B is a sectional view thereof.

FIG. 8 is a schematic diagram showing a conventional exposure apparatus.

FIG. 9 is a plan view showing a light source device of the exposure apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Panel 4 ... Shadow mask 12 ... Phosphor screen forming member layer 14 ... Light source device 15 ... Light source lamp 17 ... Optical lens system 18 ... Light amount correction filter 30 ... Cover glass

Claims (2)

[Claims] 1. A support part for positioning and supporting a panel on which a phosphor screen forming member layer is formed on an inner surface, and a light source lamp for exposing a phosphor screen forming member layer on the inner surface of the panel, which is positioned and supported by the supporting part, are provided inside. A light source device having a cover glass provided on the upper surface of the panel side, the cover glass of the light source device is convex toward both the light source side and the panel side. The exposure apparatus for a color picture tube is characterized in that the average curvature of the curved surface on the panel side is larger than the average curvature of the curved surface on the light source side. 2. A support part for positioning and supporting a panel having a phosphor screen forming member layer formed on an inner surface thereof, and a light source lamp for exposing the phosphor screen forming member layer on the inner surface of the panel positioned and supported by the supporting part are provided inside. A light source device having a cover glass on the upper surface of the panel side, the cover glass of the light source device is convex toward both the light source side and the panel side. For a color picture tube, which has a curved surface, and the amount of depression from the center of the curved surface on the panel side to the position corresponding to each axial end of the panel is in the order of the diagonal axis, the horizontal axis, and the vertical axis. Exposure equipment.