JPH0568055B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method of exposing a fluorescent surface in a color picture tube using a shadow mask integrated with an electroshield and an inner shield.

[Background of the invention]

As shown in FIG. 1, a shadow mask in a striped color picture tube has a large number of elongated slit-shaped openings arranged in rows in the vertical direction of the screen (hereinafter referred to as the Y direction). In the figure, 1 is a shadow mask, 2 is an opening, 3 is a bridge portion formed between the openings 2 in the Y direction, P _V
is the pitch of the opening 2 in the Y direction. On the other hand, the shape of the phosphor surface on the inner surface of the panel facing the shadow mask 1 is such that striped phosphors are continuously formed in the Y direction and arranged horizontally (hereinafter referred to as the X direction) for every three colors. has been done. The reason why the phosphor stripes are formed continuously without any breaks corresponding to the bridge portion 3 is to improve the irradiation margin of the electron beam.

Therefore, when performing exposure to form a fluorescent surface using a shadow mask, the bridge portion 3
A method is used to move the exposure light source so as to avoid the effects of

FIG. 2 is a diagram for explaining this exposure method. Reference numeral 4 indicates a frame that supports the shadow mask 1, 5 a panel, and 6 a linear exposure light source elongated in the Y direction. This exposure light source 6 uses arc light from a mercury lamp. The length of the exposure light source 6 is l, but since it moves in the Y direction as shown by the dotted line, its effective length is l _S. Therefore, the light irradiated onto the inner surface of the panel 5 from the openings 2 adjacent in the Y direction overlaps on the inner surface of the panel, and the portions shaded by the bridge portion 3 are also exposed.
The fluorescent surface can be exposed without being affected by the bridge portion 3. A mechanism as shown in FIG. 3 is used to move the exposure light source 6. Third
In the figure, 7 is a light source section equipped with an exposure light source 6;
8 is a stroke cam for reciprocating the light source section 7 in the Y direction. This stroke cam 8 is formed in a simple heart shape and continuously moves back and forth at a constant speed, as shown in FIG. The maximum position of the stroke corresponds to a in FIG. 2, and the minimum position corresponds to b.

The length l of the exposure light source 6 is expressed by the following equation, where P is the length from the light source to the shadow mask, and Q is the length from the shadow mask to the fluorescent surface.

l=P+Q/Q×P _VSince the values of P and Q are different between the center and the periphery of the panel, the length l of the exposure light source 6 is applied to the center, and the length of the moving stroke l _S is applied to the periphery. It is supplementing.

However, in recently developed color picture tubes that use a shadow mask, in which an inner shield is integrally formed with the shadow mask to remove the influence of geomagnetic field, the influence of this inner shield can be avoided during exposure through the shadow mask. do not have. That is, the opening of the inner shield on the electron gun side has a shape that approximates the effective surface of the fluorescent surface in order to determine the irradiation range of the electron beam onto the fluorescent surface. Therefore, the electron beam that reaches the phosphor surface through the aperture of the inner shield approximates a point light source, and unlike a linear light source for exposure, it irradiates only the effective surface area on the phosphor surface.

For this reason, in the conventional exposure method described above, when the exposure light source is moved, the fluorescent light is emitted from the upper periphery of the panel when the exposure light source is in the direction of the minimum stroke position b, and the lower periphery when the direction is the maximum stroke position a. On the surface, the shadow of the inner shield is projected onto the effective surface of the phosphor surface, reducing the amount of light by half.Furthermore, the required light source length cannot be obtained, and the influence of the bridge portion appears, resulting in underexposure of this portion. There was a problem that phosphor stripes of uniform width could not be formed.

[Purpose of the invention]

The present invention solves the conventional problems,
When exposing a fluorescent surface through a shadow mask that integrates an electron shield and an inner shield,
It is an object of the present invention to provide a method for exposing a fluorescent surface of a color picture tube in which the front effective surface is appropriately exposed.

[Summary of the invention]

In order to achieve such an objective, the present invention uses an exposure light source and a local correction filter installed above the light source, which is synchronized with the light source and not continuously, but stops at the maximum and minimum points of the stroke and reciprocates intermittently. It was designed to be moved.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail with reference to Examples.

FIG. 5 is a structural diagram showing a state in which the method for exposing the fluorescent surface of a color picture tube according to the present invention is being carried out. In the figure, 9 is an inner shield formed integrally with the shadow mask 1, and 10 is an inner shield that apparently increases the amount of light in the upper and lower peripheral areas of the panel 5.
That is, it is a filter for local correction in which a filter is deposited within the effective surface with a constant transmittance. Exposure light source 6
When reaches the maximum stroke position a, the panel 5 is masked by the open end of the inner shield 9.
Although the phosphor surface is underexposed in the peripheral area A, when the exposure light source 6 reaches the minimum position b, no shadow of the shield is projected at all. For this reason, the exposure light source 6 is moved back and forth intermittently by stopping at the maximum and minimum stroke positions for a certain period of time. As a result, the peripheral area A, where the shadow of the inner shield 9 is projected, is exposed to almost twice as much light by the combination of the local correction filter 10, and at the same time, the area other than the area A is attenuated by the area of the local correction filter 10. . That is, the part where the shield shadow is not projected is a constant light reduction area of the local correction filter 10, and in the shield shadow projection part, the light amount increases when the light source position is reached where no shield shadow is projected. . Therefore, the phosphor surface is uniformly exposed over the entire surface, and even in the peripheral area A, the phosphor stripes are formed to have a uniform width because the influence of the bridge area is removed.

Note that exactly the same operation is performed at the minimum stroke position b.

In order to intermittently move the exposure light source 6 back and forth, a heart-shaped stroke cam with a flat top as shown in FIG. 6 is used in the apparatus shown in FIG. 3. At the same time, the local correction filter 10 is also moved in synchronization. In this case, the relationship between the stroke of the exposure light source 6 and the time is as shown in FIG. Here, the maximum position of the stroke corresponds to a in FIG. 5, and the minimum position corresponds to b in FIG.

In the above embodiments, the exposure light source was moved relative to the panel using a stroke cam, but it is also possible to fix the exposure light source and move the panel in the Y direction.

〔Effect of the invention〕

As described above, according to the method for exposing the fluorescent surface of a color picture tube according to the present invention, by intermittently reciprocating the combination of the exposure light source and the local filter relative to the panel, the fluorescent surface is exposed to the effective surface. It has the excellent effect of being able to uniformly expose the entire surface of the panel, and forming phosphor stripes of uniform width even in the upper and lower peripheral areas of the panel without being affected by the bridge portion of the shadow mask.

[Brief explanation of the drawing]

Fig. 1 is a schematic partial front view of a striped shadow mask, Fig. 2 is a configuration diagram of a conventional exposure method, Fig. 3 is a perspective view of the light source movement mechanism, and Fig. 4 is a conventional A diagram showing the relationship between stroke and time, FIG. 5 is a configuration diagram of a state in which the exposure method of the present invention is implemented, FIG. 6 is a front view of the stroke cam, and FIG. 7 is a diagram showing the relationship between stroke and time of the present invention. FIG. 1... Shadow mask, 2... Opening, 3...
Bridge part, 4... Frame, 5... Panel, 6
...Exposure light source, 8, 8a...Stroke cam, 9
...Inner shield, 10...Filter.

Claims (1)

[Claims] 1. When a photosensitive resist film is formed on the inner surface of the panel of a striped color picture tube and this photosensitive resist film is exposed with a linear exposure light source through the opening of a shadow mask that is integrated with an electron shield and an inner shield, A color picture tube in which a local light intensity correction filter and an exposure light source are reciprocated in strokes relative to the panel in a direction parallel to the longitudinal direction of the opening, and are stopped for a predetermined time at the maximum and minimum points of this stroke. How to expose a fluorescent surface.