JPH0359925A - Color picture tube exposure device - Google Patents

Abstract

PURPOSE:To approximate the track of an exposure beam to an actual track of an electron beam so as to obtain a fluorescent screen of high display quality in which generation of a grid pattern and deterioration of a correcting lens are avoided by forming the fluorescent screen by means of a continuous curved surface using such a glass material that the refractive index of a correcting lens constituting an exposure device is continuously varied. CONSTITUTION:A fluorescent screen is formed by a continuous curved surface using such a glass material that the refractive index of a correcting lens constituting an exposure device is continuously varied. The continuous curved surface is combined with the curved form of the correcting lens, so that although the correcting lens is formed by a continuous curved surface the track of an exposure beam is approximated to that of an electron beam which cannot be corrected by conventional continuous curved correcting lenses. The quality of the fluorescent screen is thereby enhanced.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a color picture tube exposure device.

[Conventional technology]

Generally, a color picture tube has a phosphor film formed on the inner surface of the face panel by a black matrix made of a black light-absorbing substance and a dot or stripe-shaped phosphor film made of a trio of red, green, and blue colors. The fluorescent film of this color picture tube is formed by a method similar to that used for ordinary photographic development.

The black matrix is formed by applying a photosensitive resin that is insoluble in water in the irradiated areas, and attaching a shadow mask structure to the face panel, which is then exposed to light using an exposure device and subjected to a development process. Furthermore, after forming a film of a black light-absorbing substance (for example, graphite) on the inner surface of the face panel, the photosensitive resin is swollen with hydrogen peroxide solution and then removed by hot water spray.

Generally, a phosphor film is formed by applying a mixture of a photosensitive resin and a phosphor (commonly known as thriller) to a 7Ace panel, exposing it to light, and developing it. Some are formed by using resin and applying phosphor powder after exposure.

Exposure for forming the fluorescent film is performed using an exposure apparatus as shown in FIG.

1. Face panel 22 on which photosensitive resin film 21 is formed
After installing the shadow mask structure 23 at a predetermined distance from the inner surface of the face panel 22, the light source 24.
Correction lens 25. Light: Attached to an exposure device consisting of an lt% filter 26. The light 27 emitted from the light source 24 has its ray trajectory corrected by the correction lens 25 to match the trajectory of the actual electron beam, and its illuminance distribution is adjusted by the light intensity adjustment filter 26. It passes through and exposes the photosensitive resin 21.

[Problem to be solved by the invention]

The correction lens used in the above-mentioned exposure apparatus has a very complex curved surface in order to make the exposure light beam as close as possible to the trajectory of the actual electron beam.

Generally, a continuous curved surface is used as the curved surface of a correction lens, but such a correction lens has a limit in approximating the actual electron beam σ) trajectory. Therefore,
For example, as described in Japanese Patent Publication No. 47-40983, the curved surface of the correction lens σ is divided into regions of order, each of which forms a predetermined curved surface in the region of p, and A correction lens consisting of a so-called discontinuous curved surface with a step at the boundary has been proposed. The correction lens made of the discontinuous curved surface can very closely approximate the trajectory of the exposure light beam to the trajectory of the actual electron beam, but the exposure light beam is reflected at the step between adjacent areas.

Due to scattering, a grid pattern appears on the phosphor screen,
One thing that ruined the quality of the phosphor screen.

To solve this problem, various methods have been considered, such as reducing the step difference between adjacent areas, using an optical filter to correct the lattice pattern, and vibrating the correction lens itself, which is made of a discontinuous curved surface. . However, in order to reduce the step difference, it is necessary to increase the number of divisions, which takes time to design the complementary I lens. In addition, correction using a special optical filter is difficult to manufacture, and the method of vibrating the correction lens itself is difficult.
This has the disadvantage that the structure of the exposure apparatus is complicated and that the exposure light beam may pass through a different area due to vibration than the area through which it originally passes.

Moreover, the correction lens made of this discontinuous curved surface is
Not only is it difficult to manufacture, requiring a great deal of labor and expense, but depending on the material, near-ultraviolet light used for exposure can cause deterioration, making it impossible to use it as a correction lens.

An object of the present invention is to provide a color picture tube that can closely approximate the trajectory of an exposure light beam to the trajectory of an actual electron beam, eliminates the generation of grid patterns and deterioration of the correction lens, and provides a phosphor screen with high display quality. The purpose of the present invention is to provide an exposure device.

[Means to solve the problem]

The present invention provides an exposure apparatus in which a photosensitive resin film is coated and formed on the inner surface of a face panel, and in which exposure is performed through a shadow mask structure mounted at a predetermined distance from the inner surface of the face panel. It is formed of a continuous curved surface using a glass material whose refractive index changes continuously.

〔Example〕

Next, with reference to the drawings, 5-5 examples of the present invention will be explained. explain.

FIGS. 1(a), 1(b), and 1(c) are principle diagrams showing σ) light s and m-folding at the boundary surface of a correction lens according to an embodiment of the present invention.

11 is a medium with a refractive index nl, 12 is a refractive index n2
13 is a boundary surface of the medium, and 14 is a surface normal to the boundary surface 130.

As shown in (a) of the figure, a light ray (incident light ray) 15a that has passed through the medium 11 enters the boundary cylinder 13a, undergoes a refraction action, passes through the medium 12, and becomes the trajectory of a refracted light ray 16a. The refraction effect of this interface 13aKTh is 5nell
According to the law n1 sin θ1a=n2 sin#1H.

Here, θ1a is the angle that the incident light @15a makes with the image normal 14a, and θ2a is the angle that the refracted light 116a makes with the surface normal 14a.

The same figure (b) is a case where the boundary surface 13b is inclined,
Similarly, at the boundary surface 13b, the incident light ray 15b is refracted according to the 5nell's law, and becomes the trajectory of the refracted light ray 16b.

1. Consider obtaining the same refractive effect as in the previous figure (b) with a boundary surface 13c having a rigid oblique angle that is different from that of the boundary surface 13b, as shown in FIG. 1(C). Since the 5nall's law always holds true at the boundary surface 13c, in order to obtain the same trajectory of the refracted ray, it is sufficient to change the ratio of refractive indexes between the media.

In this case, assuming that the refractive index nl of the medium 11 is constant, the refractive index n2/ of the medium 7 is given by the following equation.

...+1) Here, n2 is the original refractive index of the medium 12, nl is the refractive index of the medium 11, and θxb is the incident ray 15b and the surface normal 14
The angle between b and σ), θ! b is the refracted ray 16b and the surface direction, 1l
The angle ψ formed by i14b is the angle formed between the boundary surfaces 13c and 13b with the counterclockwise direction being the positive direction.

From equation (1), the refractive index n2/ of the medium 17 is the original medium 1
When the refractive index n2 is greater than 2, tan ψ is positive, and the refractive index can be changed by changing the proportion of additives in the production of glass, which is a correction lens material. For example, to increase the refractive index, NazO,
By increasing the proportion of oxides with monovalent ions such as 20, or by adding highly polarizable ions such as Ba" + L a" + *p b2+ to glass-forming oxides such as
．． There are methods such as introducing into BzOs or introducing high valence ions such as Th and Ta having a large ionic radius. To reduce the refractive index, 5iCh, B20g
Increase the proportion of Na2O.

Reduce the proportion of K20 etc.

There are various ways to change the refractive index. For example, 1) changing the refractive index in the thickness direction of the correction lens material as a function of the thickness; 2) changing the refractive index in the radial direction from the center by pressing a button on the reference surface of the correction lens material. 3) change the refractive index as a function of the angle with respect to the horizontal axis relative to the reference plane of the correction lens material; 4) as a composite function that combines various of 1) to 3) above. This includes changing the refractive index.

Note that the function for changing the refractive index is not limited to the above.

〔Effect of the invention〕

As explained above, according to the present invention, a correction lens is formed using a glass material whose refractive index continuously changes.
This corresponds to changing the angle ψ between the boundary surfaces depending on the magnitude of . Therefore, by combining the curved shape of the correction lens, even though it is a correction lens consisting of a continuous curved surface,
This has the effect of approximating the trajectory of the exposure light beam, even for electron beam trajectories that could not be completely corrected with conventional continuous curved surface correction lenses.

Furthermore, since a lattice-like pattern is not generated due to steps unlike a correction lens having a discontinuous curved surface, there is no need for this correction mechanism, and a conventional exposure apparatus can be used.

[Brief explanation of drawings]

Figures 1 (ω, (b), and (C) are principle diagrams explaining the refraction of light rays at the boundary surface of the correction lens of the present invention, respectively, and Figure 29 is a schematic configuration diagram of an example of a conventional fluorescent screen exposure device. 11...Medium (refractive index nl), 12...
・Medium (refractive index nz), 13a, 13b, 13c...
...-Boundary surface, 14a, 14b, 14c...=...Surface normal, 15a. 15b...Incoming light beam, 16a, 16b...
...Refracted ray, 17...Medium (refractive index n2,
21... Photosensitive It oil film, 22... Face panel, 23... Shadow mask structure,
24... Light source, 25... Correction lens,
26...Light amount adjustment filter, 27...
·light.

Claims (1)

[Claims] In an exposure device in which a photosensitive resin film is coated and formed on the inner surface of a face panel, and exposure is performed through a shadow mask structure mounted at a predetermined distance from the inner surface of the face panel, the refractive index of a correction lens constituting the exposure device is A color picture tube exposure device characterized by being formed of a continuous curved surface using a glass material that changes continuously.