JPS629972B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a color picture tube phosphor surface having regularly arranged phosphor stripes.

As is well known, the fluorescent surface of a color picture tube is formed by forming a photosensitive resin film mixed with a phosphor on the inner surface of the face panel, and placing a photosensitive resin film on this film through a shadow mask near the electron beam deflection point. When exposed to light from a high-pressure mercury lamp, only the exposed parts of the photosensitive resin film are cured, and if the uncured and unexposed parts are washed away by a development process using hot water spray, etc., only the exposed parts of the inner surface of the face panel, that is, the desired areas, are cured. It is manufactured using a baking method in which the phosphor remains attached.

An ultra-high pressure mercury lamp used as a light source for printing the phosphor of a striped color picture tube is usually arranged with its discharge tube axis, that is, the direction of the positive column of the arc discharge, parallel to the slot of the shadow mask. Due to the discharge characteristics of ultra-high pressure mercury lamps, the thickness of the arc,
That is, the inner diameter of the discharge tube is limited to a range of 1.0 to 2.5 mmφ, and the inner diameter of the discharge tube cannot be made thinner outside this range, or conversely, cannot be made thicker outside this range. When a light source with such a finite width is used, all the light emitted from the entire width of the light source reaches the photosensitive resin film surface, while only the light emitted from a part of the width of the light source reaches the surface of the photosensitive resin film. The light from the remaining part of the slot is blocked by the edge of the slot and does not reach the slot, and the light emitted from any direction in the width direction of the light source is blocked by the shadow mask and does not reach at all.
There are three types of locations. That is, between a place where all the light from the light source reaches and a place where no light from the light source reaches, there is an intermediate area where the illuminance gradually changes over a certain finite (not infinitesimal) width. The attachment of the phosphor by the baking method takes advantage of the reaction of photosensitive resin that hardens when exposed to light, and separates areas where the phosphor remains attached to form stripes and other areas where it is washed away. Because of the existence of the above-mentioned intermediate area, the width of the phosphor stripe may vary due to slight variations in the amount of light from the light source, such as due to voltage or usage time, or slight differences in the quality of the photosensitive resin. It is difficult to obtain a clean, sharp linear contour because the periphery becomes wider or narrower, or there are areas that fall off. If it were possible to use a geometrically linear (infinitely small) powerful light source, the width of the intermediate area where the illuminance gradually changes would become infinitesimal, and the above problem would be solved, but of course such a light source does not exist. do not.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing phosphor stripes in which the problems associated with the conventional method for manufacturing phosphor stripes by printing are reduced.

In order to achieve the above object, in the present invention,
A hyperboloid lens parallel to the linear light source is inserted between the shadow mask and the linear light source, and a phosphor is formed on the inner surface of the picture tube face panel through this lens and the shadow mask. It was decided to expose the resin film. In this way, the apparent or, in other words, effective width of the linear light source relative to the photosensitive resin film surface can be reduced almost uniformly over the entire inner surface of the face panel.

The features of the present invention will be specifically explained below by comparing a conventional case with an embodiment of the present invention regarding a lamp house of a light source used for phosphor stripe printing.

FIG. 1 is a sectional view of an example of a conventional lamp house. A quartz plate 2 is watertightly attached to a light projection window of a lamp house body 1. An ultra-high-pressure mercury lamp 3 is installed inside the lamp house body 1 and the quartz plate 2, and cooling water 4 is flowed around the discharge tube 5 to generate heat from the arc discharge inside the tube. The discharge tube 5 made of quartz is prevented from being damaged by melting. In this example, the outer diameter of the discharge tube 5 is 4.0 mmφ, the inner diameter is 1.0 mmφ, the distance from the center 6 of the discharge tube 5 to the inner surface of the quartz plate 2 is 4 mm, and the thickness of the quartz plate 2 is 4 mm. The refractive index of quartz is approximately 1.5, and the refractive index of water is approximately 1.3, which are quite similar values, so there is little effect of refraction at the interface between quartz and water, and the light from this lamp house is visible from the face panel. The width of the light source is approximately 1.0 mm, which is approximately equal to the inner diameter of the discharge tube.

FIG. 2a is a perspective view according to an embodiment of the present invention, showing a quartz plate 2a provided with a hyperboloid 7 and an ultra-high pressure mercury lamp 3 arranged parallel to the hyperboloid 7. FIG. 2b is a cross-sectional view of the lamp house according to the embodiment of the present invention, where 7 is a hyperboloid, 8 is its asymptote, and other symbols are the same as in FIG. 1. It is a thing. This hyperboloid has a focal distance of 14.0 mm and a shortest distance between the hyperboloid and the focal point of 2.0 mm. The distance between the center 6 of the discharge tube 5 and the inner surface of the quartz plate 2a is 4 mm as in the case of FIG. 1, and the thickness of the quartz plate 2a is 4 mm at its thinnest point from the vertex of the hyperboloid 7 to the opposite inner surface. The thickness at the thickest point on the periphery of hyperboloid 7 is 6.5 mm. In this case as well, since the refractive indices of quartz and water are similar, the quartz discharge tube 5 of the mercury lamp 3, the cooling water 4, and the quartz plate 2a having a hyperboloid 7 are combined into one hyperboloid. It can be thought of as forming a lens. When the hyperboloid surface 7 of the quartz plate 2a is directed toward the ultra-high pressure mercury lamp 3, the difference in refractive index between water and quartz is small as described above, so it is difficult to obtain the effect of the hyperboloid surface, which will be described later. When using this lamp house, the effective light source width seen from the center of the panel is 0.6 mm, and when the deflection angle is 110°, the effective light source width seen from the panel periphery is 0.5 mm, and the light source width is uniformly spread over almost the entire inner surface of the panel. This means that we were able to reduce the

In the past, there have been proposals to insert a lens between the light source and the shadow mask in order to reduce the effective width of the light source as seen from the panel. If a 15mmR cylindrical surface is installed at position 7, the effective light source width at the center of the panel is 0.6mm, and at the periphery of the panel is 0.3mm.
mm, or in the case of a 20mmR cylindrical surface, at the center of the panel.
There was a large difference between the center and the periphery of the panel, with the difference being 0.7mm and 0.5mm at the periphery of the panel. The lens according to the present invention using this point hyperboloid has a large curvature near the central apex as a property of the hyperboloid, and the curvature decreases as it approaches the periphery. It becomes possible to make the reduction ratio as seen from the periphery almost equal. In addition, in the case of conventional proposals, there is an example in which the surface with a large curvature of the lens faces the light source side. When water passes between the surface and the discharge tube, the lens effect on that surface weakens because the difference in refractive index between water and quartz is small. If, in order to avoid this situation, the ultra-high-pressure mercury lamp itself is equipped with an inner tube and an outer tube and is cooled by itself, a large lens for reducing the effective light source width will be required, and sometimes electronic The arrangement may be difficult in relation to the correction lens used to correct the difference between the beam and the light. Furthermore, in order to make the effective light source width reduction rate uniform between the center and the periphery, a lens with a cross section similar to a Fresnel lens has been proposed, which is a combination of many parts of cylindrical lenses each having a different radius of curvature. With such a lens, uneven illuminance always occurs at the stepped portion, which is inconvenient in practice.

Next, the effect of narrowing the effective light source width will be explained using FIG. 3. FIG. 3a is a diagram showing the intensity distribution of light irradiated on the photosensitive resin film formed on the inner surface of the face panel through one slot of the shadow mask in the width direction of the slot width, that is, the width of the light source. The dotted line indicates the case where the hyperboloid lens is not used, and the dotted line indicates the case where the hyperboloid lens is used. That is, the true shadow area BC or B'C', and the penumbra area AB, which are determined by the light source width, the shadow mask slot width, the distance between the light source and the shadow mask, and the distance between the shadow mask and the photosensitive resin film surface.
It has CD or A′B′, C′D′. When the hyperboloid lens according to the present invention is used, the width of the penumbra, that is, the intermediate region where the illuminance gradually changes, decreases, and the true shadow increases. FIG. 3b is a diagram showing the exposure dose distribution when forming phosphor stripes of a constant width W without using a hyperboloid lens or using a hyperboloid lens. This corresponds to when a curved lens is not used and when it is used. Here, the exposure amount distribution is proportional to the light intensity distribution, but the exposure amount Io at the edge of the stripe width W is a constant value (the minimum exposure amount required for the phosphor to remain attached during washing and development, which is the critical exposure amount). become). As is clear from FIG. 3b, the total exposure amount within the range of the stripe width W is larger when a dotted line, that is, a hyperboloid lens is used. Therefore, when a hyperboloid lens is used, the margin against stripe drop is improved.

As explained above, according to the present invention, it is possible to reduce the effective light source width at a large rate almost uniformly over the entire inner surface of the panel as seen from each position, and the adhesive strength around the phosphor stripes can be reduced. The effect is that the margin against stripe dropout is improved.

Although the above description has been made regarding the formation of phosphor stripes, it is clear that the invention can be similarly applied to the formation of black matrices.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional lamp house, FIG. 2 a is a perspective view of an embodiment of the present invention, FIG. 2 b is a sectional view of a lamp house of an embodiment of the present invention, and FIGS. 3 a and b FIG. 3 is a diagram illustrating the effect of reducing the effective light source width. 1... Lamp house body, 2, 2a... Quartz plate, 3... Ultra-high pressure mercury lamp, 4... Cooling water, 5...
Discharge tube, 7... hyperboloid.

Claims (1)

[Claims] 1. A step of forming a film containing a photosensitive resin on the inner surface of the face panel of a color picture tube, and a step of exposing this film to light through a shadow mask and developing it to form a predetermined pattern of the film on the inner surface of the face panel. A color picture tube fluorescent surface manufacturing method comprising: bringing the other surface side of a hyperboloid lens, in which one surface is a hyperboloid and the other surface is a flat surface, into contact with cooling water for cooling the linear light source for exposure, and disposed parallel to and facing the linear light source at a predetermined distance;
A method for manufacturing a color picture tube fluorescent surface, characterized in that the film is exposed to light emitted from the linear light source and passed through the hyperboloid lens and the shadow mask.