JPH02223127A - Formation of phosphor film face - Google Patents

Abstract

PURPOSE:To manufacture a delicate high-intensity phosphor film face with a two-layer structure of a phosphor layer and a conductor layer in one process by forming a layer containing many phosphor grains and a layer containing many conducting grains by electrodeposition with an electrodeposition liquid adjusted with the quantity of free ions. CONSTITUTION:Phosphor grains and conducting grains with the grain size relatively smaller than that of phosphor grains are dispersed in an organic dispersion medium, metal salt is added to the suspended liquid and stirred, and metal ions are adsorbed on dispersed grains and electrified. An electrodeposition liquid 1 adjusted with the quantity of free ions is manufactured by replacing all or part of the dispersion medium with a new dispersion medium. A layer containing many phosphor grains and a layer containing many conducting grains are formed on a board 3 by electrodeposition with this electrodeposition liquid. A delicate high-intensity phosphor film face with a two-layer structure of at least a phosphor layer and a conductor layer can be manufactured in one process.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for forming a phosphor surface by electrophoretic electrodeposition.

[Prior Art] Methods for forming a phosphor surface include a precipitation method, a coating method, a printing method, and an electrodeposition method, each of which is used in fields that take advantage of their characteristics. Among these, the electrodeposition method has the advantage that it can produce a wide range of films from thin to thick, has a smooth surface, and can obtain dense films in a short time. Also,
The electrodeposition method is also advantageous in that it is easy to pattern the phosphor film and there is no need to decompose and remove the organic binder.

On the other hand, in low-speed electron beam emission, providing conductivity to the phosphor surface prevents charge-up and lowers the accelerating voltage, so a highly conductive phosphor surface is needed. Furthermore, in order to increase the brightness, it is necessary to increase the density of the phosphor particles.

In order to satisfy both of these requirements at the same time, it is necessary to control the structure of the phosphor film surface. That is, it is preferable to form a two-layer structure including a phosphor layer on the observation side and a conductor layer on the electron beam irradiation side.

However, conventionally, in order to form a film surface with such a structure, two or more steps have been required regardless of whether the method is a coating method or an electrodeposition method.

[11 Problems to be Solved by the Invention] The present invention was made in view of the above circumstances, and its purpose is to provide a dense and high-luminance material having a two-layer structure of a phosphor layer and a conductor layer. An object of the present invention is to provide a method for forming a phosphor surface that can produce a phosphor film surface in one step.

[Means to solve the problem]

This invention is above! In order to solve this problem, in a method for forming a conductive phosphor surface on a substrate by electrodeposition, phosphor particles and conductive particles having a relatively smaller particle size than the phosphor particles are mixed in an organic dispersion medium. A metal salt such as aluminum nitrate is added to the suspension and stirred to cause each of the dispersed particles to adsorb metal ions and become electrically charged, and then centrifugation or the like is used to remove all of the dispersion medium. Alternatively, prepare an electrodeposition solution in which the amount of free ions is adjusted by replacing a portion of the dispersion medium with a new dispersion medium, and use the electrodeposition solution to coat a substrate with a layer containing many phosphor particles and a layer containing many conductive particles. It is characterized by being formed by electrodeposition.

[For production]

When electrodeposition is performed using the above electrodeposition solution, the amount of free ions in the dispersion medium is small, so adsorbed ions separate from the dispersed particles during electrodeposition, resulting in a decrease in the charge on the particles. come. Therefore, at the initial stage of electrodeposition, phosphor particles with a large particle size also adhere, but as the charge decreases, the proportion of conductive particles with a small particle size increases. As a result, a two-layered phosphor film surface is formed in which a layer of phosphor particles is deposited on the substrate and a layer of conductive particles is deposited thereon.

Therefore, according to the present invention, a two-layered phosphor film surface can be formed in one step. Note that the thicknesses of the phosphor layer and the conductor layer can be controlled by the amount of powder charged, the initial amount of metal salt added, and the amount of replacement of the dispersion medium. Further, by repeating electrodeposition, it is also possible to form a phosphor film surface having a repeating structure of phosphor layers and conductive layers.

[Example 1] 2 cc of 3% aqueous solution of aluminum nitrate was added to 148 cc of isopropyl alcohol, and to this was added ZnS s Ag-based phosphor powder with an average particle size of 7 μm and In with a particle size of 1 μm or less.
0.45 g of g03 conductive powder was added.

In10! The proportion of conductive powder was 154% of the total amount of powder. After thorough stirring, the suspension was heated at 1000 r, p.
, s for 10 minutes, and the supernatant was removed.

150 cc of isopropyl alcohol was added and stirred well to obtain an electrodeposition solution.

FIG. 1 is a schematic sectional view showing an example of an electrodeposition apparatus, in which a glass plate substrate 3 coated with an ITO conductive film 2 is placed in the electrodeposition liquid 1.
A counter electrode 4 made of stainless steel was arranged, and while stirring the electrodeposition liquid 1 with a stirrer 5, a voltage of 100 V was applied between the electrodes 3 and 4 so that the substrate 3 side became the negative electrode, and was maintained for 10 minutes. Next, electrodeposition was performed on another substrate under the same conditions using the same electrodeposition solution 1 to prepare a plurality of electrodeposition samples.

Figure 2 shows the brightness measured using each of the above electrodeposited samples, and as the electrodeposition progresses, the Into,
It can be seen that the ratio increases and the brightness decreases. The horizontal axis in the figure indicates the cumulative time during which voltage was applied to the electrodeposition solution 1 until the sample was electrodeposited, and the In□0. The increase in the percentage of
This was also confirmed by scanning electron microscopy (SEM) observation of the electrodeposited film.

[Example 2] The amount of the aluminum nitrate aqueous solution added is Ice,
An electrodeposition solution was prepared in the same manner as in Example 1. Electrodeposition was performed using this electrodeposition solution at 100 V for 20 minutes.

As a result, a dense electrodeposited film with a thickness of about 20 μm was formed. As a result of 38M observation, it was found that this film had a two-layer structure in which a phosphor layer was attached to the substrate and a conductor layer was present thereon.

[Example 3] Using the same electrodeposition solution as in Example 2, electrodeposition was performed at 100V for 20 minutes, and then a new electrodeposition solution was used for another 100 minutes.
Electrodeposition was carried out for 5 minutes at V. As a result, the formed electrodeposited film had a sandwich structure consisting of a phosphor layer, a conductor layer, and a phosphor layer. Such a layered structure is suitable for applications such as fluorescent display tubes.

〔Effect of the invention〕

As described above, the present invention involves dispersing phosphor particles and conductive particles having a relatively smaller particle size than the phosphor particles in an organic dispersion medium, adding a metal salt to the suspension, and stirring. Then, each of the dispersed particles is adsorbed with metal ions and charged, and then,
An electrodeposition solution is prepared in which the amount of free ions is adjusted by replacing all or part of the dispersion medium with a new dispersion medium, and the electrodeposition solution is used to coat a substrate with a layer containing a large amount of phosphor particles and a conductive layer. Since the layer containing many particles is formed by electrodeposition, a dense and high-brightness phosphor film surface having at least a two-layer structure of a phosphor layer and a conductive layer can be produced in one step. It is possible to provide a method for forming a phosphor surface.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing an example of an electrodeposition apparatus, and FIG. 2 is a graph showing the luminance of the electrodeposition liquid with respect to the cumulative voltage application time. 1... Electrodeposition liquid, ITO conductive film, 3... Substrate, 4...
- Counter electrode, 5... Stirrer.

Claims (1)

[Claims] (1) In a method of forming a conductive phosphor surface on a substrate by electrodeposition, phosphor particles and conductive particles having a relatively smaller particle size than the phosphor particles are dispersed in an organic dispersion medium. , a metal salt is added to the suspension and stirred to adsorb metal ions to each of the dispersed particles and charge them, and then all or part of the dispersion medium is replaced with a new dispersion medium to increase the amount of free ions. A phosphor surface, characterized in that a layer containing a large amount of phosphor particles and a layer containing a large amount of conductive particles are formed on a substrate by electrodeposition using the electrodeposition liquid prepared by preparing an electrodeposition liquid containing a large amount of conductive particles. How to form.