JPS59165342A - Color cathode ray tube - Google Patents

Abstract

PURPOSE:To eliminate various effects of reflected rays of light at the time of exposure and thereby to obtain a high quality of phosphor screen free from color irregularity in a CRT of high resolution, by using a glass panel provided with pits having depth corresponding to the dimension of the picture element and being distributed in high density over the same. CONSTITUTION:A fine-pitted surface 1b is provided on the internal surface of the panel portion 1a on which a phosphor surface is to be formed. The average depth of the pits is 2 to 10mum and the density of the pits is 5X10<5> to 8X 10<6>cm<-2>. After a resist film 5 has been spread over the internal surface of the glass panel portion 1a, the surface is exposed to light. Then, the ray of light R4 tending to be reflected toward the side of the mask 3 by the pitted surface 1b on the internal surface of the panel portion 1a is scattered there and loses its regularity, and the ray of light R5 entering the panel portion 1a and reflected by the external surface thereof is also deprived of its directional property and therefore the ray of light R6 returning to the resist film 5 has no periodicity to interfere with the primary light L. As a result, no moire is produced and no periodical change in the exposed dimension occurs, and a phosphor screen having a good uniformity being macroscopically free from color irregularity can thus be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color cathode ray tube having a shadow mask type fluorescent surface structure.

Conventionally, color cathode ray tubes have been known that have a shadow mask type phosphor surface structure in which a phosphor layer is surrounded by a black light absorbing layer for the purpose of improving the contrast performance of images.

FIG. 1 is a partially cutaway side view of a conventionally used shadow mask type color cathode ray tube. In this diagram,
(1) is a glass bulb, (2) is a fluorescent screen provided on the panel part (1a), and (3) is the screen (2).
) is opposed to the shadow mask, and (4) is an electron gun that emits three electron beams for blue, green, and red.

A method of manufacturing the above color cathode ray tube will be explained with reference to FIG. After the photocurable photosensitive resist film (5) is formed on the inner surface of the panel part (1a) as shown in (6) of the same figure,
), a shadow mask (
G (green), B (blue), R (
Exposure from the light source position (red) is performed sequentially. Next, the photocurable photosensitive resist film (5) is developed using hot water spray, etc., at the position where the photosensitive resist film (5) is to be formed.
Hardened resist dots (stripe) (6) are formed as shown in FIG.

Next, a solution in which graphite is dispersed in an aqueous solution containing a small amount of binder, for example, is applied to the inner surface of the first panel portion (1a) and dried to form a graphite-based black light-absorbing coating film (7) as shown in FIG. Next, for example, hydrogen peroxide (H
Graphite-based black light-absorbing coating film (7) using IO water, etc.
After decomposing the hardened resist dots (stripes) (6) through the panel, for example, spray pressurized water or the like and develop the inner surface of the panel part (1a) to form the hardened resist dots (stripes) (6) Graphite-based black light-absorbing dots (stripe) (8) are formed at the positions other than those previously shown in FIG. 1 (G). Thereafter, as shown in the same figure (g), a photocurable slurry film (9) containing, for example, a green-emitting phosphor is applied and dried, and then, as shown in FIG. G (
Exposure is performed from the light source position (green).

Next, apply a photocurable slurry film (9) using hot water spray, etc.
When development is performed, green 0 luminescent phosphor dots (stripes) are formed as shown in FIG.

Thereafter, in the same manner, phosphor dots (stripe) of other two colors, ie, blue 0 and red phosphor dots (stripes) (11) and (2), were formed, and then these phosphor dots (stripe) were formed. Aluminum (
A metal film (131) consisting of a thin film (At) is formed by known means, thereby completing the production of the fluorescent screen (2) of the color cathode ray tube.

However, as in a high-resolution color cathode ray tube, when the dimensions of the picture elements of the fluorescent screen (2), that is, the aperture diameter (or stripe width) of the light-absorbing dots (stripe) (8) become smaller, the same In Figure (6), the resist film (
5), the light (1) is reflected on the inner surface of the panel part (1a) as shown in FIG. 3, and the reflected light (Rs) is further reflected on the outer surface of the mask (3) to form a resist film ( The light (R1) that returns to the resist film (5) overlaps with the light that is reflected on the outer surface of the panel portion (1a) and returns to the resist film (5), and the light interference becomes significant. 5), a diamond-shaped moire appears, and when a stripe-shaped resist film is formed, a blind-shaped moire appears, and the light-absorbing dots (stripe) in the same figure (g) appear.
(8) The opening diameter and stripe width become non-uniform.

As a result, when the fluorescent screen (2) in this color cathode ray tube is made to emit light with an electron beam, color unevenness or brightness unevenness inherent to the fluorescent surface appears, resulting in a problem of lowering the screen quality.

As a way to avoid this problem, conventional resist film (5)
There have been methods to mix dyes into the film, and methods to mix inorganic pigments such as alumina, silicon oxide, and titanium oxide as light dispersants, but these methods have been insufficiently effective, and have side effects in achieving uniform film formation. There were various drawbacks, such as the difficulty of

The present invention has been made in order to eliminate the above-mentioned drawbacks, and provides a color cathode ray tube with no color unevenness by preventing periodic reflected light incident on the resist surface.

An embodiment of the present invention will be described below.

As shown in Fig. 4, the glass panel part (1a) is made by placing molten glass material between an outer mold and an inner mold (plunger) and press-molding it to form a fluorescent surface. A fine pit surface (1b) is formed on the inner surface of the panel portion (1a).
) is formed. This pit surface (1b) is determined by the surface condition of the plunger. By changing the method of processing the surface of the plunger, various types of plungers can be produced, ranging from those with few to many irregularities. However, in general, with this type of method, the unevenness becomes striae-like and it is not possible to obtain fine pits, so after this process, high hardness fine particles are sprayed to mechanically create fine pits, and hydrofluoric acid is The surface is finished by applying a solvent to the glass. Further, similar surface processing can be achieved simply by chemical etching.

A resist film (
When 5) is applied and exposed, light (
R4) has no regularity due to scattering, and the panel part (1a
) The light (Rs) that passes through the interior of the resist film (5) and is reflected at the outer interface also loses directionality, so the light (Rs) that returns to the resist film (5) again
R6) has no periodicity with respect to the -order light (L) K, and as a result, it does not cause moiré, and has uniformity without macroscopic color unevenness without periodic changes in the exposure dimension. A good fluorescent screen (2) is obtained.

This effect is especially great in the fluorescent screen (2) for high resolution among color cathode ray tubes, and the aperture diameter or stripe width (d) of the light-absorbing dots (stripe) (8) shown in Fig. 5 is particularly effective. It was effective when the width (width of the portion corresponding to the phosphor stripe) was 50 to 120 μm.

The hole shape of the black matrix, which should originally be circular, has a chrysanthemum pattern with uneven edges because it is a bit, and a sawtooth pattern in the case of a stripe shape, but because the bit density is set high, it looks macroscopic. This has the effect of reducing unevenness caused by masks, etc.

Furthermore, even if external light hits the fluorescent surface, it will be scattered, which has the secondary effect of making the image easier to see.

As described above, in the color cathode ray tube according to the present invention, by using a glass panel with a pit depth corresponding to the fluorescent surface pixel size and a high pit density as a high-resolution tube, various reflected lights generated during exposure can be reduced. It has the advantage of being completely free from the effects of color and providing a high-quality fluorescent surface with no uneven color.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side view of a color cathode ray tube in which the present invention is implemented, and FIGS. 3 is a sectional view of a main part showing an example of a conventional photosensitive resist film forming process. FIG. 4 is a sectional view of a main part showing an example of a photosensitive resist film forming process of the present invention. The figure is a sectional view of essential parts showing an example of the fluorescent screen structure of the present invention. (1)...Glass bulb, (la)...Glass panel portion, (2)...Fluorescent screen, (3)...Shadow mask, (3a)...Aperture, -(41. ...Electron gun, (5)...Photosensitive resist film, (7)...Black light absorption film, (8)...Black light absorption dot (stripe), QOI, (Ill, +121... Fluorescent dots (stripe). In the figures, identical parts indicate the same or equivalent parts. Agent Makoto Kuzuno (1 other person)

Claims (1)

[Claims] (1) A resist film pattern corresponding to the openings of the shadow mask is formed by exposing the photosensitive resist film formed on the inner surface of the glass panel section, and the openings corresponding to the openings of the shadow mask are formed through the photosensitive resist film. In a color cathode ray tube, a fluorescent screen consisting of fluorescent dots or stripes is formed in the openings of the black light absorbing film, and the average depth is 2 to 10 μm and the density is On the inner surface of the glass panel part in which numerous pits of 5 x 10' to 8 x 10' cm were formed, the opening diameter or stripe width of the black matrix was 50 cm.
A color cathode ray tube characterized in that a fluorescent screen having a diameter of 120 μm is formed.