JPH03156829A - Electrodepositing device and method therefor - Google Patents

Abstract

PURPOSE:To obtain electrodeposition substrates with excellent fluorescent screen characteristic and uniform thickness by providing ultrasonic oscillating elements for dispersing phosphor grains in an electrodeposition liquid, and sticking phosphor grains on the substrates by electrophoresis with this electrodeposition liquid. CONSTITUTION:An electrodeposition liquid dispersed with phosphor grains is stored in a cylindrical container 1, a rotary shaft 3 rotated by a driving motor is provided in the container 1, and a hexagonal pillar-shaped supporter 4 is integrally formed on the rotary shaft 3, for example. Six electrodeposition substrates 5 are polygonally assembled and supported on faces of the outer periphery of the supporter 4. Segment electrodes 6 are arranged on the outside of electrodeposition substrates 5, and segment electrodes 6 and opposite electrodes 7 are immersed in the electrodeposition liquid 2 face to face. A power source 8 is connected between opposite electrodes 7 and segment electrodes 6. Ultrasonic oscillating elements 10 such as piezoelectric elements are fitted to the outer periphery wall section 11 and the outside bottom section 12 of the container 1 and connected to a ultrasonic oscillator, and the oscillation output can be adjusted. A fluorescent screen with a small gap between grains is obtained.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an electrodeposition apparatus and an electrodeposition method, and more particularly to an electrodeposition apparatus and an electrodeposition processing method for forming a fluorescent surface in a fluorescent display tube. be.

[Prior art]

A fluorescent display tube has a fluorescent surface formed on a large number of segment electrodes arranged in a single row or multiple rows in one direction, and is sealed together with a hot cathode in a vacuum container, and the hot cathode generates thermoelectrons. , selectively applying a positive voltage to the segment electrodes according to the information to be displayed attracts thermoelectrons to one selected segment, and the fluorescence emitted when the attracted thermoelectrons collide with the fluorescent surface , a display element that displays information, and is known as a bar code display tube or a fluorescent dot array tube.

As a method of forming a good fluorescent surface on the segment electrodes in such a fluorescent display tube, a method using electrophoresis is known (for example, Japanese Utility Model Publication No. 57-55728).

This method involves immersing a substrate on which a segment electrode array is formed into a dispersion liquid in which phosphor particles are dispersed, and applying a voltage between a counter electrode facing the segment electrode array and the electrode array. Fluorescent particles are attached to segment electrodes. The distance between the segment electrodes and the opposing electrodes, the so-called opposing gap, and the electric field strength determined by the applied voltage are important factors in the electrophoresis method.

However, it is difficult to attach phosphor particles only on the segment electrodes by controlling the electric field alone, and improvements have been made to utilize the flow of the electrodeposition solution and to further increase its stability. are doing.

By the way, about the electrodeposition liquid! In general, an organic solvent such as alcohol containing a charge/stabilizer such as a metal salt is used as a dispersion medium, phosphor particles are added as a dispersoid, and the phosphor particles are stirred with a stirring device. are dispersed. If this dispersion is insufficient, agglomeration of the phosphor particles in the liquid will occur, and when a voltage is applied between the electrodes,
Since aggregates adhere to the electrode, a fluorescent surface with non-uniform N thickness and large interparticle gaps is formed.

As a stirring device, a blade-type or botter-type homogenizer or starsee is generally used.

After the stirring by the stirring device is completed, the electrodeposition liquid is transferred to an electrodeposition liquid storage container, and the image electrode is further immersed to perform the adhesion process. There are problems such as the fact that the adhesion process cannot be carried out at the same time and the particles re-agglomerating between the end of stirring and the start of the adhesion process (including the time until the liquid flow stops).

Generally, the particle size of the phosphor particles used in the above-mentioned electrodeposition is about 1 to several microns. Regarding the relationship between particle size and emission intensity, it is known that when the particle size decreases to 1 μm or less, the emission intensity also decreases.
In addition, in the case of a dot array tube, due to the conflict with the resolution (segment electrode width is about 0.1 -),
It is thought that phosphor particles having a particle size of approximately several microns are used. Furthermore, particles with a smaller particle size are
Since the cohesive force is large, there arises the disadvantage that it becomes an aggregate and adheres during electrodeposition.

〔the purpose〕

The purpose of the present invention is to improve the above-mentioned problems, mainly to improve the dispersibility of phosphor particles in an electrodeposition solution, and to achieve a uniform layer thickness even when fine particles with a large cohesive force are used. An object of the present invention is to provide an electrodeposition device and an electrodeposition method that enable the formation of a fluorescent surface with small gaps.

〔composition〕

The present invention relates to an electrodeposition apparatus for attaching phosphor particles to a substrate by electrophoresis, which is characterized in that an ultrasonic oscillation element is attached to disperse phosphor particles in an electrodeposition solution. A uniform electrodeposition solution is created by dispersing the phosphor particles while emitting a deposition device and ultrasonic waves, and then this electrodeposition solution is used to adhere the phosphor particles to the substrate by electrophoresis. A method of electrodeposition, a step of uniformly dispersing the phosphor particles in an electrodeposition solution, and a step of electrodepositing the phosphor particles onto a substrate using an electrophoresis method. Ultrasonic waves are emitted throughout the two steps. The present invention relates to three inventions of electrodeposition methods characterized by continuous deposition.

More specifically, in an apparatus for depositing phosphor particles onto a large number of segment electrodes arrayed on a substrate using an electrophoresis method, an ultrasonic oscillation element is placed in a container containing an electrodeposition solution. The present invention relates to a method characterized in that phosphor particles are dispersed by ultrasonic waves or are attached to a substrate while being dispersed by ultrasonic waves using a device characterized in that they are installed.

The electrodeposition apparatus of the present invention supports an electrodeposition substrate on which segment electrodes facing a counter electrode are arranged, and immerses the electrodeposition substrate in an electrodeposition liquid in an electrodeposition liquid storage container. The electrodeposition liquid during electrodeposition is stirred by the method described above, and a voltage is applied between the segment electrode and the counter electrode, so that the phosphor particles dispersed in the electrodeposition liquid are attached only to the segment electrodes. It is the kind of device that can be used.

In the present invention, an ultrasonic oscillation element attached to the electrodeposition apparatus for dispersing phosphor particles in the electrodeposition liquid is attached to the outer peripheral wall or bottom of the electrodeposition liquid storage container. Regarding the number of ultrasonic oscillation elements to be installed and their mounting positions, it is preferable that the ultrasonic oscillation elements be arranged and mounted evenly so that the ultrasonic waves are uniformly transmitted to the electrodeposition liquid.

In addition, a piezoelectric element is used as an ultrasonic oscillation element, and as a piezoelectric element, lead zirconate titanate (PZT) is particularly used.
is preferred.

The ultrasonic oscillation device connected to the ultrasonic oscillation element is preferably one with variable oscillation output.

The material for the electrodeposition liquid storage container may be any material as long as it is resistant to organic solvents, has a certain degree of mechanical strength, and can efficiently transmit ultrasonic waves. For example, stainless steel is preferable.

The ultrasonic treatment used in the present invention has a frequency of 25 to 50K) I
z, oscillation output lO~30Id/Q with respect to the volume of the liquid container
The treatment time varies depending on the treatment method, but is usually 1 minute or more, preferably 5 minutes or more.

In the present invention, the phosphor particles include ultrafine particles that cannot be uniformly dispersed and agglomerate using normal dispersion methods.
For example, the particle size (average) is 0.5 μm or less, preferably 0.5 μm or less.
It is also possible to use particles with a diameter of 1 μm or less, more preferably 0.08 μm or less, particularly preferably 0.05 μm or less.

In the present invention, ultrafine phosphor particles having the above particle size can be used in combination with conventional phosphor particles (average particle size of 1 μm or more). When used together, the ultrafine particles less than 1 μm account for at least 10 wt% of the total particles, preferably 30 wt%.
, particularly preferably 7 (ht%).

Note that usable phosphor materials include all known phosphor materials. For example, ZnO1ZnS:Z
n, ZnS:CuAl2, Y, O, S:Eu, etc.

Various alcohols including isopropyl alcohol can be used as the dispersion medium constituting the electrodeposition solution, and known charge stabilizers made of various metal salts such as AQ (No.) 39H20 are added to this. be able to.

Specific examples of the electrodeposition method including ultrasonic treatment of the present invention include:
(A) A method of starting the application of voltage between the Q-segment electrode and the counter electrode at the same time as the end of the ultrasonic dispersion of the phosphor particles in the electrodeposition solution, (B) (C) A method of starting the application of voltage between the segment electrode and the counter electrode while performing ultrasonic dispersion, and (C) a method of reducing or stopping the ultrasonic oscillation output after applying the voltage between the segment electrode and the counter electrode. Among the above methods, method (C) is the most preferred.

The drawings showing a specific example of the electrodeposition apparatus of the present invention will be described.

An electrodeposition liquid 2 in which phosphor particles are dispersed is contained in a cylindrical container 1 made of stainless steel or the like. A rotating shaft 3 rotated by a sliding motor (not shown) is provided in the container 1, and a polygonal column, for example, a hexagonal columnar support 4 is integrally formed on the rotating shaft 3. There is. Six electrodeposited substrates 5 are supported on each outer peripheral surface of the support body 4 in a polygonal combination to form a cylindrical body, and constitute a rotating body that is rotated integrally with the rotating shaft 3. Here, the electrodeposited substrate 5
Segment electrodes 6 are arranged at a predetermined pitch according to the intended function of the fluorescent display tube.
are assembled in a hexagonal shape so that Therefore, each segment electrode 6 faces a counter electrode 7,
And, it is immersed in the electrodeposition liquid 2.

Here, the counter electrode 7 is constituted by a rod-shaped body bent into a substantially U-shape and having a circular cross section. It is fixed to prevent any misalignment. A power source 8 is connected between the counter electrode 7 and each segment electrode 6.

The state of electrical continuity between the power source 8, each segment electric bottle 6, and the counter electrode 7 is simply shown in the figure, but in reality, for example, a conducting wire commonly connecting each segment electrode is connected to the circumferential surface of the rotating shaft 3. It can be obtained by leading to a conductor ring and pressing each end of the power source 8 to this conductor ring in the form of a motor brush. This also applies to the counter electrode 7. A rotary blade 9 is provided at the lower end of the rotary shaft 3 to promote stirring of the electrodeposition liquid 2 in order to prevent sedimentation of the phosphor particles. By rotating the rotating shaft 3 in the direction of the arrow, the segment electrode 6 and the container 1 are rotated relative to each other, and an appropriate liquid flow is generated between the opposing electrode and the electrodeposited substrate. Coupled with the rotation, the phosphor particles are successfully adhered to the segment electrode 6, which is the surface to be electrodeposited.

The ultrasonic oscillation element 1o, such as a piezoelectric element, is attached to the outer peripheral wall 11 and outer bottom 12 of the container 1, and is connected to an ultrasonic oscillation device (not shown) so that the oscillation output can be adjusted. .

An example of the arrangement of the ultrasonic oscillation element 10 attached to the container 1 is shown in FIG.
is shown upside down in FIGS. 3 and 4.

Example 1 AQ for isopropyl alcohol 6Q as electrodeposition liquid
100 μm of CNo.)3.9H20 was dissolved, and 5 g of ZnO phosphor ultrafine particles with an average particle size of 0.05 μm were added thereto, and electrodeposition was performed using the electrodeposition apparatus shown in the example described above. I did this.

First, the electrodeposition liquid 2 is ultrasonically dispersed in the container 1, and at the same time, the rotation X9 is rotated at 600 rpm. At the same time as the ultrasonic oscillation was stopped, a voltage of 20 to 40 V was applied for 60 seconds between the segment electrode 6 and the counter electrode, which were opposed to each other at an interval of 10 m, to adhere ultrafine phosphor particles onto the segment Tft Fln 6. SEM observation of the fluorescent surface revealed that a fluorescent surface with smaller gaps between particles and particles more uniformly adhered to it than when the same fixing solution was used without any ultrasonic treatment was obtained.

Example 2 Using the same equipment and fixer as in Example 1, first apply 2 electrodeposition liquids.
After dispersing ultrasonic waves with an oscillation output of 50 W and applying a voltage between both electrodes under the same conditions as in Example 1, the ultrasonic oscillation output was gradually decreased for 90 seconds to stop the ultrasonic oscillation, and at the same time The voltage application was also stopped. As a result of the SEM rating of the fluorescent surface,
Compared to the results of Example 1, the gaps between the particles were slightly smaller, and a uniform fluorescent surface was obtained.

Example 3 Electrodeposition solution 2 was prepared by dissolving 50rrIg of AQ (No, ), 9H,O in 3Q of isopropyl alcohol, and adding 5g of ZnO phosphor particles with an average particle size of 1.5 μm to this solution.
, 1 g of ZnO phosphor ultrafine particles having an average particle size of 0.05 μm were mixed, added, and dispersed by ultrasonic waves.
Using the electrodeposition apparatus used in 2008, the rotary blade 9 was rotated at 600 rpm for stirring, and a voltage of 20 to 40 V was applied for 1 minute between the segment electrode 6 and the counter electrode 7, which were opposed to each other at an interval of 1 ounce. The phosphor was electrodeposited only on.

Electron microscope observation of the obtained fluorescent surface revealed that it had a structure in which the gaps between the fluorescent particles were filled with ultrafine fluorescent particles. Furthermore, when the amount of cathodoluminescence for this substrate was measured, it was found that it increased by about 8% compared to the case where ultrafine phosphor particles were not added.

〔effect〕

Since the electrodeposition apparatus of the present invention has a simple configuration in which an ultrasonic oscillation element is installed in an electrodeposition liquid container, an electrodeposition substrate with excellent fluorescent surface characteristics can be obtained at a low cost with a simple operation. It will be done.

Further, in the electrodeposition method of the present invention, an electrodeposited substrate with excellent fluorescent surface properties can be obtained by a simple method of controlling ultrasonic dispersion and the order and manner of applying voltage between electrodes.

Further, it is possible to use ultrafine phosphor particles having an extremely small particle size, and with these ultrafine particles, an electrodeposited plate with a uniform layer thickness and a very low porosity can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a side cross-sectional view of an electrodeposition apparatus used to produce the phosphor-attached substrate of the present invention, FIG. 2 is a cross-sectional view taken along the line A-A in FIG. 1, and FIGS. 3 and 4 are ultrasonic waves. FIG. 3 is a perspective view showing an example of arrangement of oscillation elements. 1... Container 2... Electrodeposition liquid 3... Rotating shaft 4... Support 5... Electrodeposition substrate 7... Counter electrode 9... Rotating blade 11... Container outer peripheral wall 6 ... Segment electrode 8 ... Power supply 10 ... Ultrasonic oscillation element 12 ... Outer bottom of the container

Claims (1)

[Claims] 1. In an electrodeposition device for depositing phosphor particles onto a substrate by electrophoresis, an ultrasonic oscillation element is attached to disperse the phosphor particles in the electrodeposition solution. Characteristic electrodeposition equipment. 2. A uniform electrodeposition solution is created by dispersing the phosphor particles while emitting ultrasonic waves, and then the phosphor particles are attached to the substrate by electrophoresis using this electrodeposition solution. Electrodeposition method. 3. It consists of the step of uniformly dispersing the phosphor particles in the electrodeposition solution, and the step of electrodepositing the phosphor particles on the substrate by electrophoresis, and is characterized by continuing to emit ultrasonic waves during both steps. Electrodeposition method.