JPS6158936B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to an improved method for forming the fluorescent surface of a color picture tube. The phosphor surface of a color picture tube is formed by three types of phosphor dots regularly arranged in a triangular or linear shape on the inner surface of the face plate, which emit green, blue, and red light when irradiated with an electron beam. Formation of the phosphor dots is typically accomplished as follows. First, a green slurry in which green-emitting phosphor particles are suspended in a photosensitive binder is uniformly applied to the inner surface of a well-washed face plate and dried. Next, a shadow mask with a large number of holes corresponding to the arrangement pattern of the dots is exposed to light, and the green-emitting phosphor at the position where it is to be left as dots is photocured. Next, development is performed to remove the unexposed areas of the slurry.
Forms phosphor dots that emit green light. In the same way, phosphor dots that sequentially emit blue and red light are formed at predetermined positions on the inner surface of the face plate. After the phosphor dots of three colors are formed in this manner, a film such as a lacquer is formed on the surface thereof. Furthermore, a metal such as aluminum is deposited by vacuum deposition to form an aluminum thin film on the film. A baking process is then performed to incinerate the binder and film of the phosphor dots, leaving only the phosphor and the aluminum deposited film on the inner surface of the faceplate. Thereafter, a funnel is sealed to the face plate by a predetermined method, then an electron gun is attached and sealed, and the product is evacuated to a high vacuum. Although the color picture tube is formed by the above-mentioned steps, the reason for forming the film and the aluminum vapor deposited film will be described below. In other words, when the picture tube is in operation, the phosphor dots are struck by the electron beam emitted from the electron gun and emit light, which is emitted almost equally into and out of the face plate. A metal film, ie, an aluminum film, is deposited on the surface of the fluorescent dot, and has a mirror surface that allows electrons to easily pass through and has a high light reflectance. However, when aluminum is deposited directly onto the phosphor dots, it is difficult to form a mirror surface because it is deposited intermittently along the irregularities of the formed phosphor dots, resulting in poor reflection efficiency and, therefore, a decrease in brightness. decreases. In order to eliminate such problems, a removable film is formed on the phosphor dots by heat treatment before aluminum is vapor-deposited onto the phosphor dots, and an aluminum evaporated film is formed on the film. . A water-soluble acrylic emulsion is commonly used to form such a film, and the method is to inject the emulsion solution onto the inner surface of the face plate on which the phosphor dots are formed and apply it while rotating. The film is formed by rapid drying. At this time, if the film is formed without sufficiently covering the phosphor, problems such as the phosphor particles 2 being exposed in the aluminum film 1 and causing cracks and uneven brightness occur, as shown in FIG. . Therefore, in order to prevent this from occurring, it is sufficient to form a thick film so as to completely cover the phosphor particles. However, as the film becomes thicker, during the baking process after forming the aluminum evaporated film, the diffusion of oxygen into the film becomes insufficient, resulting in a so-called unbaked residue phenomenon where the film partially ashes and remains. As a result, there is a drawback that the brightness characteristics are deteriorated. The present invention provides an improved method for forming the fluorescent surface of a color picture tube so as to eliminate this drawback. That is, an organic peroxide is mixed with an emulsion solution to form a film solution, this is applied onto a group of phosphor dots to form a film, and an aluminum evaporated film is formed on top of the film to prevent cracking. Obtain a thin film with excellent reflection efficiency. In this case, the organic peroxides added to the emulsion solution to be applied include ditertiary butyl peroxide [C(CH ₃ ) ₃ OOC(CH ₃ ) ₃ ], benzol peroxide,

[Formula] etc. are used, and if such an emulsion solution is applied to form a film, it will decompose during the baking process and release oxygen, so unlike conventional methods, oxygen will diffuse sufficiently and there will be no unburnt residue on the film. does not occur. Examples of the present invention will be described below. Acrylic resin emulsion, such as B-74 (trade name) manufactured by Nippon Acrylic Co., Ltd., is adjusted to 15 to 20% by adding water, and then ditertiary butyl peroxide is added to 5 to 20% of the solid content of B-74. Add and stir to mix thoroughly. The emulsion solution thus obtained is applied so as to sufficiently cover the phosphor dots 12 formed on the inner surface of the face plate 11 shown in FIG. 2, and then heated and dried to form a smooth thick film 13. form. Next, an aluminum vapor deposition film 14 is formed and a baking process is performed to obtain a fluorescent surface. In this way, a phosphorescent surface was obtained on which an aluminum film with extremely good reflection efficiency was formed without any unburned film. The luminous efficiency of this phosphorescent surface has been improved by 5% to 10% compared to the conventional method. As described above, by using the emulsion solution of the present invention, even if the phosphor is sufficiently coated to form a film, it is possible to prevent the film from being left unburned, and a phosphor surface with an excellent metal vapor deposited film can be obtained. , can contribute to improving the characteristics of color picture tubes.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a fluorescent surface formed on a face plate, and FIG. 2 is a cross-sectional view of the fluorescent surface according to the present invention. DESCRIPTION OF SYMBOLS 11... Face plate, 12... Fluorescent dot, 13... Film, 14... Aluminum vapor deposition film.

Claims (1)

[Claims] 1. Sequentially applying several types of phosphors on the inner surface of the face plate to form groups of several types of phosphor dots at predetermined positions, and then applying an emulsion solution thereon to form a film; A color picture tube characterized in that, in manufacturing a fluorescent surface of a color picture tube by forming a metal vapor deposited film on this film, an organic peroxide is added to the emulsion solution and applied to form a film. Method of forming a fluorescent surface.