JPS58192242A - Manufacture of metal backing cathode-ray tube - Google Patents

Abstract

PURPOSE:To degrade interface tension and fully wet the inside of a phosphor layer by adding an organic solvent, which is a good solvent, to a macro-molecule forming a thin film of an organic macro-molecule substance. CONSTITUTION:A water solution containing 2.5wt% of ethyl acetate is injected onto a phosphor layer 7 in order to form an even water solution layer 8 while removing the surplus water solution. Next, the toluene solution containing 3.5wt% of an acryl resin is sprayed on the water solution layer 8 in an atomized form followed by drying and forming a thin film 9 of an acryl resin on the inside of a phosphor layer 7 by evaporating moisture and a solvent to obtain a metal backing layer 10 by evaporating aluminium thereon. Thereafter the thin film 9 of the acryl resin is dissolved by heating. The phosphor layer 7 can be fully wetted because the interface tension of the ethyl acetate water solution is low compared with that of water and moreover ethyl acetate is a good solvent to the acryl resin. By said method, the smooth metal backing layer able to show a full effect to the phosphor layer consisting of phosphor particles having water repellency can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a cathode ray tube having a metal back using a metal such as aluminum on the inner surface of a phosphor layer.

When forming a metal back layer by vapor depositing a metal such as aluminum on the fluorescent surface of a cathode ray tube, obtain a smooth metal back layer, that is, a metal back layer that does not have uneven spots when observed from the front of the face glass. For this reason, in the past, appropriate pretreatment was performed to further eliminate the unevenness of the inner surface of the 671 phosphor j. For example, the first
As shown in the figure, the phosphor layer 1-2 attached to the inner surface of the face glass 1 of the 11-electrode tube is wetted with water, and the unevenness is filled with water 3 to make the inner surface of the phosphor layer 2 appear smooth. After spraying a solution of an organic polymer bath agent onto it in the form of a spray gun, it is dried, and the water and bath agent are evaporated to form the organic polymer Fu1i#4 into a phosphor. It is formed on layer 2 (8), and a metal such as aluminum is deposited thereon to obtain a smooth metal back 1-5. Yes +! The thin film 4 of the monomolecular substance is removed by heating in the next step.

However, since the surface of the phosphor layer is not water-repellent, the surface of the phosphor layer (2) may not be sufficiently resistant to water, and the unevenness on the inner surface of the phosphor layer may not be completely removed by water. Puncture 7m S was also not smooth at times. For this reason, the effect of the metal back layer could not be fully demonstrated, and the product value was significantly reduced.

The present invention provides a method for forming a smooth organic polymer layer for a phosphor layer.

In the present invention, an organic solvent is added to reduce the interfacial tension of water in order to sufficiently wet the inner surface of the phosphor layer. Furthermore, this @solvent is preferably one that is a good solvent for the polymer forming the thin film of the organic polymer substance. The necessity of being a good solvent is that when a thin film of an organic molecular substance is formed, conventionally, the solvent used to dissolve the polymer substance, such as toluene, is completely dried; −
If the water that wets the phosphor layer also contains a good solvent for the polymer, the formation of a thin organic polymer film will be delayed until the water that has trapped the phosphor layer dries, and it will adapt to the unevenness of the phosphor layer. It is assumed that a thin film of organic polymer is formed.

Part of the measurement results of the interfacial tension of a water bath solution containing an organic solvent is shown in Part 2-2.
g'7>. Methyl ethyl ketone (a) 4w shown here
t% aqueous solution and 1wt% of inbutyl alcohol (b)
When comparing a water bath solution containing 3 acrylic resin and a toluene bath solution containing S wt % as a spray solution, the one containing methyl ethyl ketone, which is a good solvent for acrylic resin, was better than the one containing isobutyl, which is a Kg medium for acrylic resin. I was able to get a better metal back than the one that contained alcohol. Note that a is the characteristic when 19U1Mi25U. Further, C is a property of water.

In addition, using a water bath solution of 10 wt≠ of methyl ethyl kent, acrylic resin 3. Swt% toluene solution t”J
When used as Nobu Q, water (6) sufficiently wetted the phosphor layer 2, but the interfacial tension of the water@liquid was too low, so the toluene solution did not spread into the water #4 and remained locally. A thin film of +#i^ molecules was formed only locally.

From this, it can be seen that the cooling of organic matter is due to the interfacial tension of the water bath liquid (
The condition is that 25U) is not smaller than 401 V n Al1.

-h1 Kents, -When the number of carbon atoms of alcohol and acetic acid esters exceeds 8, these organic solvents have poor solubility in water, resulting in a low interfacial tension [does not show the Tow effect]. Also, when the number of carbon atoms is 8 or more, the part point is 200.
If the temperature is close to C, evaporation will be slow and production E will be inconvenient.

Note that a method using a molecular water bath has been proposed in order to facilitate the retention of water that wets the phosphor layer and facilitate manufacturing, but if this polymer precipitation does not occur, the organic An aqueous solution containing both a solvent and a polymer may be used as the liquid for wetting the phosphor 1-.

Examples of the present invention will be shown below. As shown in FIG. 3, phosphor powder is applied to the inner surface of the face glass 6 of the cathode ray tube to form a phosphor layer 7. A water bath solution containing 2.5 wt% of ethyl acetate was injected onto the phosphor InT.
Excess aqueous solution is removed to form a uniform aqueous solution layer 8.

Next, a toluene solution containing 35wt9 acrylic resin is sprayed onto the water bath liquid layer 8 and then turned and frozen to evaporate the water and solvent and form a thin film S of acrylic resin on the inner surface of the phosphor layer 1. A metal back layer 10 was obtained by steaming aluminum on top of the metal back layer 10. The acrylic resin thin film 9 was decomposed by this heat removal. The aqueous solution of ethyl acetate used in this example has a lower interfacial tension than water, so it can sufficiently capture the phosphor layer 7, and ethyl acetate is a good solvent for acrylic resin. It is.

By the method described above, it is possible to form a smooth metal back layer that is sufficiently effective for the phosphor 1- made of water-repellent phosphor particles.

Brief explanation of Fig. 1 Fig. 1 is a cross-sectional view of a part of the face of the cathode arm to explain the method of forming a metal back on a conventional fluorescent light. Figure 3 is a cross-sectional view of a portion of the face of the *Tsubaki m-tube used to explain the method of forming a metal back on the fluorescent surface of the present invention. be.

6.--face glass, 7.φ. phosphor layer,
8... Water bath liquid layer, 9, eφ, thin film, 10, fist e@metal bank r-1

Claims (1)

[Claims] A phosphor is coated on the inner surface of the face of the cathode ray tube, and the inner surface of this phosphor layer is wetted with an aqueous solution containing a ketone with a carbon number of 7 or less or an ester with a carbon number of 7 or less consisting of a monohydric alcohol and acetic acid. A method for manufacturing a metal back cathode ray tube, which comprises forming a thin film of a polymer substance on the water bath liquid, forming a metal puncture layer on the thin film, and then performing a firing process.