JP2812483B2 - Electrodeposition equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrodeposition apparatus used for forming a fluorescent screen in a fluorescent display tube, a phosphor dot array tube, or the like.

2. Description of the Related Art Conventionally, a fluorescent display tube has a phosphor screen formed on a large number of segment electrodes formed in a single row or a plurality of rows in one direction, sealed in a vacuum vessel together with a hot cathode, and generates thermoelectrons from the hot cathode. On the other hand, selectively applying a positive voltage to the segment electrodes according to the information to be displayed, attracts thermions to the selected segment electrodes, and the attracted thermoelectrons are
An element for displaying information by the fluorescence emitted when colliding with a phosphor screen, and is known as a barcode display tube or a phosphor dot array tube.

Therefore, here we take a phosphor dot array tube as an example,
The outline of the fluorescent display tube will be described with reference to FIG. 9 and FIG. Usually, an electrodeposited substrate 1 formed of a glass plate, a ceramic plate, a resin plate or the like is provided. On the electrodeposited substrate 1, a series of segment electrodes 2 are arranged in a line in the longitudinal direction of the substrate, and a fluorescent screen 3 is formed on the surface of each segment electrode 2. Here, in reality, the dot size of each fluorescent screen 3 is extremely small, about 1/10 mm, and it is difficult to show the same ratio at the same ratio. Therefore, in FIG. This is greatly exaggerated.

On the electrodeposited substrate 1, dielectric layers 4a and 4b are formed on both sides in the direction of arrangement of the fluorescent screens 3 in the longitudinal direction, and grid electrodes 5a and 5b are formed on these dielectric layers 4a and 4b, respectively. Are formed. Furthermore, tungsten wires 6a and 6b (surfaces coated with an electron-emitting substance) 6a and 6b as hot cathodes are stretched over the grid electrodes 5a and 5b in the longitudinal direction of the electrodeposited substrate 1. Reference numeral 7 denotes a face member made of a transparent material such as a glass plate, which is in close contact with the grid electrodes 5a and 5b and is integrated on the electrodeposited substrate 1.

Thus, the electrodeposited substrate 1, the dielectric layers 4a and 4b, the grid electrodes 5a and 5b, and the face member 7 have a closed vacuum space 8 therein.
In the vacuum space 8, the segment electrode 2, the phosphor screen 3, the tungsten wires 6a, 6b, etc. are confined and are highly evacuated. The segment electrode 2 includes an electrode portion and a lead wire portion. The electrode portion has a substantially square shape and a size of about 20 μm to 100 μm in length and width, and the width of the lead wire portion is also about 20 μm to 100 μm. The segment electrode 2 has a strip shape in which the electrode portion and the lead wire portion are integrated, and the fluorescent screen 3 is formed on the tip of each segment electrode 2.

In such a configuration, an appropriate voltage is applied to the grid electrodes 5a and 5b in advance, and the following equation 1 is applied to the tungsten wires 6a and 6b.
When an alternating current of 0 mA flows, the tungsten wires 6a and 6b are heated by Joule heat and emit thermoelectrons. In this state, for example, when a positive voltage is applied to one of the segment electrodes 2 to make this electrode a positive potential, the thermoelectrons are attracted to the electrode portion of the segment electrode to which the voltage is applied and are absorbed by the electrode portion. Inevitably, the energy state of the fluorescent substance on the fluorescent screen 3 is excited. The excited fluorescent material is
When returning to the ground state, it emits fluorescence, and this fluorescence is observed via the face member 7.

In such a fluorescent display tube, as a method of forming a good fluorescent screen on the segment electrode, for example,
A method using electrophoresis is known as disclosed in Japanese Patent Application No. 55728.

This is the electrodeposition substrate on which the segment electrode rows are formed,
Immerse in the dispersion liquid in which the phosphor particles are dispersed, apply a voltage between the counter electrode facing the segment electrode row and this segment electrode row, and attach the phosphor particles in the dispersion liquid onto the segment electrode. It is to let. Here, the opposing electrode and the segment electrode row are arranged to face each other in parallel. Also, when the gap between these electrodes, that is, the so-called opposing gap is viewed from the surface of the electric field, the smaller the voltage, the larger the electric field intensity can be obtained even if the applied voltage is small. In the electrophoresis method, since the dispersed particles move in a liquid in accordance with the electric field intensity, the factor of the electric field intensity is quite important.

However, it is extremely difficult to control only the electric field by attaching the phosphor particles only to the segment electrode rows and not to the other portions. It has been empirically found that scraping and removing is effective.

In view of this, there is a type in which a liquid flow is generated by stirring the inside of a liquid layer with a rotating blade, for example, a propeller-like stirring member, or by circulating the liquid with a pump or the like. However, there is a limit to the stability of the flow, particularly when the electrode surface size is large or when the segment electrode arrangement density is large, because the dispersion of a predetermined concentration is not stably supplied to the electrode facing gap, There is a problem that dense attachment of the phosphor particles to the segment electrode cannot be expected.

Various methods have been proposed to solve such problems. For example, according to Japanese Patent Application No. 60-45168, in order to electrodeposit phosphor particles on a large number of segment electrodes arranged and formed on an electrodeposited substrate, the electrode is opposed to a segment electrode on a substrate immersed in a dispersion liquid. The width in the direction orthogonal to the segment electrode arrangement direction of the counter electrode arranged in parallel to the segment electrode arrangement surface at the position where A system for stably and reliably circulating supply is shown. Also,
According to Japanese Patent Application Nos. 61-134280 and 62-178484, in order to electrodeposit phosphor particles on a large number of segment electrodes arranged and formed on an electrodeposition substrate, an electrode in which phosphor particles are dispersed is used. The liquid is stored in a container, and the electrodeposition substrate is formed in a polygonal shape via a holding member for the electrodeposition substrate around a rotation axis provided in the container, so that the stability of liquid stirring is increased. Discloses a method for densely adhering phosphor particles.

These methods provide a novel method for electrodeposition, but in any method, a portion other than the segment electrode, for example, a phosphor is selectively applied by an electric field formed between the segment electrode and the counter electrode. The wiring part that is drawn out to emit light, the insulator part between the segment electrodes, or
It is unavoidable that the phosphor adheres to the insulator and the like provided on the wiring portion. That is, the electrodeposition of the phosphor particles by the electrophoresis method uses an electrodeposition solution in which the phosphor particles are dispersed, and forms an electric field between the segment electrode serving as the electrode to be electrodeposited and the counter electrode, and The phosphor particles are selectively attached only to the electrodes, but the phosphor particles are physically attached to the other portions or are located at the top when the substrate is pulled up from the electrodeposition liquid. The electrodeposition liquid flows between the segment electrodes by flowing to the lower part, and furthermore, the phosphor particles form a chain at the time of electrodeposition and bridge between the segment electrodes, so that fluorescent light is not required to adhere to unnecessary parts. Body particles may be attached.

Since such a phenomenon is not preferable as the electrodeposition quality, in reality, phosphor particles adhering to unnecessary portions on the electrodeposited substrate which has been subjected to the electrodeposition treatment by such an electrodeposition apparatus are subjected to a post-process. And is removed by various methods such as cutting and polishing. However, with such a mechanical removal method, it takes time in the inspection / repair process, and the wiring pattern portion and the segment electrode are damaged, and the removed particles are left behind between the wiring patterns, which may cause a disconnection or a short circuit. This often causes problems such as a poor connection with a drive circuit and a failure to emit light from a desired segment electrode during use. In particular, since such a phenomenon tends to increase with the deterioration of the electrodeposition liquid, the life of the electrodeposition liquid is affected. Therefore, it is necessary to reduce such a phenomenon as much as possible.

For this reason, when the phosphor particles are electrodeposited on the segment electrodes by electrophoresis, the mask member is used as much as possible to prevent the phosphor particles from adhering to portions other than the segment electrodes on the electrodeposited substrate. There has been proposed an electrodeposition method for performing electrodeposition. Here, the mask member is formed, for example, by a part of a holding member that holds the electrodeposited substrate in the electrodeposition liquid. If the processing in this case is shown in the order of steps, “attaching the electrodeposited substrate to the holding member” → “immersing in the electrodeposition liquid” → “energizing (electrodeposition)” → “pulling up from the electrodeposition liquid” → The process of “drying the electrodeposited substrate” → “removing the electrodeposited substrate from the holding member” is repeated.

Problems to be Solved by the Invention However, even if a mask member is used during electrodeposition, there is no guarantee that the electrodeposited portion can be electrodeposited with high precision. It is merely intended to reduce the adhesion as much as possible.

Means for Solving the Problems The present invention electrodeposits phosphor particles by an electrophoresis method using an electrodeposition liquid in which phosphor particles are dispersed on a large number of segment electrodes arrayed and formed on an electrodeposition substrate. In such an electrodeposition apparatus, a post-electrodeposition immersion means for immersing the electrodeposited substrate immediately after electrodeposition with a liquid having the same properties as the electrodeposition liquid is provided, and after immersion, the electrodeposition substrate and the liquid The direction of separation of the separation means for separating the electrodes is set to a direction different from the direction of arrangement of the segment electrodes on the electrodeposited substrate.

The electrodeposited substrate on which the electrodeposited liquid that has adhered immediately after electrodeposition is not completely dried is immersed in a liquid having the same properties as the electrodeposited liquid by the immersion means after electrodeposition. At the time of separation, the direction of separation is set to a direction different from the direction of arrangement of the segment electrodes, so that adverse effects on the adjacent segment electrodes due to the removed phosphor particles are minimized.

Embodiment An example serving as a premise of the present invention will be described with reference to FIGS. 1 and 2. FIG. The same parts as those shown in FIGS. 9 and 10 are denoted by the same reference numerals.

First, FIG. 2 shows the electrodeposition step. This is accomplished by the steps described above, ie,. "Attaching the electrodeposited substrate to the holding member" →. "Immersion in electrodeposition liquid" →. "Electrification (electrodeposition)" →. "Pulling from electrodeposition liquid" →. “Drying of electrodeposited substrate” →. In the repetitive process of “detaching the electrodeposited substrate from the holding member”, after the “pulling up from the electrodeposition liquid” step and before the “drying the electrodeposited substrate” step,. "Immersion of the electrodeposited substrate immediately after electrodeposition in a liquid having the same properties as the liquid constituting the electrodeposition liquid" →. The step "pulling and separating the electrodeposited substrate from the liquid" is performed.

That is, immediately after the completion of predetermined electrodeposition, the electrodeposited substrate is immersed in a liquid having the same properties as the liquid constituting the electrodeposition liquid. This liquid is the “liquid having the same properties as the electrodeposition liquid” in the present invention.
Shall be called. Here, as the normal electrodeposition solution, isopropyl alcohol _{((CH 3) 2 · CHOH} ) aluminum nitrate as a control agent _{(Al (NO 3) 3 ·} 9H 2 O) was added,
A dispersion of a zinc oxide phosphor (ZnO: Zn) is used. As the liquid A having the same properties as the electrodeposition liquid,
For example, a liquid having mutual solubility with isopropyl alcohol (IPA), for example, a polar organic solvent such as ethyl alcohol (C ₂ H ₃ OH), methyl alcohol (CH ₃ OH), or water (H ₂ O) is used.

As shown in FIG. 1, in addition to the electrodeposition liquid container 10, a liquid A for accommodating the liquid A and serving as a dipping means after the electrodeposition is carried out, as shown in FIG. A container 11 is provided. Here, the electrodeposition process will be described with reference to FIG. First, FIG. 1A shows the electrodeposited substrate 1 held by the holding member 12. This electrodeposited substrate 1 has a large number of segment electrodes arranged and formed in the same manner as in the above-described conventional method. FIG. 1B shows a state in which such an electrodeposited substrate 1 is immersed in an electrodeposition liquid 13 contained in an electrodeposition container 10 by a holding member 12. Here, while the electrodeposition liquid 13 is immersed, the stirring blade 14 provided in the electrodeposition vessel 10 is rotationally driven to stir the electrodeposition liquid 13 and perform a desired electrodeposition treatment as in the related art. Then, the phosphor particles are electrodeposited on the segment electrodes of the electrodeposited substrate 1 by electrophoresis. When the electrodeposition is completed, the electrodeposited substrate 1 is pulled up and separated from the electrodeposition liquid 13 by the lifting of the holding member 12, and returns to the state shown in FIG. That is, the processing steps (1) to (3) are performed between FIGS. 1 (a) and 1 (b).

Here, in the conventional case, the electrodeposited substrate 1 pulled up and separated from the electrodeposition liquid 13 is dried, but the electrodeposition liquid on the electrodeposition substrate 1 is promptly dried without drying, as shown in FIG. like,
It is immersed in the liquid A in the liquid A container 11 (step).
After the immersion, the electrodeposited substrate 1 is pulled up from the liquid A, separated from the liquid A, and the process shifts from a drying process to a detaching process from the holding member 12. As described above, by immersing the electrodeposited substrate 1 immediately after electrodeposition and before drying in the liquid A having the same properties as the electrodeposition liquid 13, the segment of the phosphor layer which should be originally adhered can be disturbed. Phosphor particles adhering to unnecessary portions between and around the electrodes can be removed. This can be interpreted as dilution using the liquid A which is a polar organic solvent.

By the way, if the electrodeposited substrate 1 is immersed in the liquid A in a state where the deposited electrodeposition liquid is dried, the deposited layer of the phosphor particles adhered by the electrodeposition is dried once, and the liquid A Is satisfied, the particles having weak adhesive force are separated from each other or between the particles and the electrode as the electrodeposition surface, and after the electrodeposited substrate 1 is pulled up from the liquid A, the phosphor particle layer is The phenomenon of being disturbed occurs. This disturbance appears as a short circuit between adjacent segments, uneven light emission intensity, and the like.

The electrodeposited substrate 1 immediately after the electrodeposition was simply immersed in the liquid A and pulled up, but as shown in FIG.
A stirring blade 15 may also be provided in the container 11 to stir the liquid A as in the case of electrodeposition. However, the stirring strength of the liquid A is preferably weaker than the stirring strength of the electrodeposition liquid 13 during electrodeposition. Such an intensity relationship is easy because stirring is performed to remove adhered particles only at unnecessary portions without disturbing the phosphor particle layer on the predetermined electrodeposited surface that has migrated and adhered at the time of electrodeposition. Understand. In the state of immersion in the liquid A, vibration may be applied to the electrodeposited substrate 1 via the holding member 12 instead of stirring.

Next, a modified example of an example which is a premise of the present invention will be described with reference to FIGS. The immersion time for the liquid A is controlled in consideration of the fact that a problem occurs when the immersion time for the liquid A is too long.

First, as an example in which a problem occurs when the liquid A is immersed in the liquid A for a long time, there is a method of forming a phosphor screen as disclosed in, for example, JP-A-61-267224. That is, before electrodeposition, slits 17 (or dots) are formed by the pattern of the photoresist layer 16 as shown in FIG.
In this case, phosphor particles are electrodeposited only on the exposed portion 17 and then burned out by passing the photoresist layer 16 through a baking furnace to form phosphor screens 3 (phosphor dots). is there. In the case of this method, if IPA as described above is used as the electrodeposition liquid, the photoresist is dissolved in the IPA, and before immersion in the electrodeposition liquid, the surface is cured by irradiating ultraviolet rays. If it is immersed for too long a time, it will eventually dissolve into the electrodeposition liquid 13 or into the liquid A. This may enter between the phosphor particles and remain even in a burnout in a later process, which may lower the luminous efficiency as the phosphor.

Therefore, it is necessary to control the immersion time in the liquid A, and the electrodeposited substrate 1 may be pulled up and separated from the liquid A before the photoresist dissolves into the IPA. However, in a production apparatus that operates continuously, not only this process but also other processes are required, which is limited. For example, in the case of performing the electrodeposition process, as shown in FIG. 4, the production apparatus uses the substrate attaching / detaching process position P ₁ , the electrodeposition process position P ₂ (corresponding to FIG. 1 (b)), and the liquid A immersion. Rotary transfer member for process position P ₃ (corresponding to FIG. 1 (c)) and drying process position P ₄
The process of sequentially transferring the electrodeposited substrate 1 to each process position by the rotation of 18 (to which the holding member 12 is attached) is repeated to produce. Here, since the time for moving in the direction of the arrow in FIG. 4 is determined, it is necessary to independently control the immersion time in the liquid A immersion step without affecting other steps.

Then, after a predetermined time has passed from the liquid A immersion state (corresponding to FIG. 1 (c)) as shown in FIG. 5 (a), the electrodeposition substrate 1 is separated from the liquid A by electrodeposition. The substrate 1 (holding member 12) is left as it is, and the liquid A container 11 side is lowered by separating means (not shown) as shown in FIG. 5 (b). According to this, the electrodeposited substrate 1 can be controlled arbitrarily immersion time while keeping the position in the liquid A dipping process position P _3. Before the electrodeposition substrate 1 for subsequent immersion come is transferred to the liquid A dipping process position P _3, it is sufficient to increase the displacement of the liquid A container 11 to its original position. Thus, the immersion time can be quickly controlled only by controlling the lowering / rising of the liquid A container 11 by the separating means.

Further, another modified example of the premise of the present invention is the seventh modified example.
This will be described with reference to the drawings. It relates to control of the immersion time for the liquid A. Auxiliary tank 19 with lid in liquid A container 11
Are connected by a flexible pipe 20, and the position of the auxiliary tank 19 can be displaced between a position higher and a position lower than the liquid container 11 by separating means (not shown).

First, when the electrodeposited substrate 1 is immersed in the liquid A in the liquid A container 11, the auxiliary tank 19 is located higher than the liquid A container 11 as shown by the solid line. When the predetermined immersion time has elapsed, the auxiliary tank 19 is displaced to a position lower than the liquid A container 11 as shown by the phantom line in FIG. Then, the liquid A in the liquid A container 11 moves into the auxiliary tank 19. That is, the container 11 for liquid A
By removing the liquid A from the inside, the electrodeposited substrate 1 is released from the immersion state, and is separated from the liquid A. Therefore, the immersion time can be arbitrarily controlled by controlling the displacement of the auxiliary tank 19. Again, before the electrodeposition substrate 1 for subsequent immersion come is transferred to the liquid A dipping process position P _3, the auxiliary tank 19 to the original position is raised displaced container liquid A liquid A
You can put it back within 11.

Further, still another modified example of the premise of the present invention will be described with reference to FIG. The immersion time is controlled by withdrawing the liquid A from the liquid A container 11, but a pump 22 is provided together with the auxiliary tank 21, and a circulation pipe provided with valves 23 above and below the liquid A container 11. Connected by 24.

In such a configuration, the liquid A container 11 is usually filled with the liquid A, and is used for immersion of the electrodeposited substrate 1.
Then, when a predetermined immersion time has elapsed, the valve 23 is opened,
The liquid A in the liquid A container 11 moves into the auxiliary tank 21. As a result, the liquid A in the liquid A container 11 is drained, and the immersion of the electrodeposited substrate 1 is released, as in the previous embodiment. Then, the next electrodeposition substrate 1 for immersion is
Before coming is transferred to the immersion step position P _3, the pump 22 is driven together with the closed or the valve 23, the liquid A in the auxiliary tank 19 is returned to the liquid A container 11. In this case, if a filter is provided in the circulation pipe 24, foreign substances in the liquid A can be removed.

An embodiment of the present invention will be described with reference to the drawings.
In the present embodiment, the directionality when separating the electrodeposited substrate 1 from the liquid A is devised. First, the arrangement direction of the segment electrodes 2 on the target electrodeposited substrate 1 (the arrangement direction of the phosphor dots) is set to the arrow S direction shown in FIG. Therefore,
When the electrodeposited substrate 1 is immersed in the liquid A and then separated from each other, the separation direction does not match the arrangement direction S.

For example, in the case of FIG. 1, assuming that the vertical direction in the drawing is substantially the segment electrode arrangement direction, the liquid A in FIG.
At the time of pulling and separating from the state of immersion into the state of FIG. 3A, an inclination is provided between the pulling direction and the direction of arrangement of the segment electrodes. More specifically, the lifting operation may be performed by slightly tilting the holding member 12 serving as the separating unit.

In order to separate the electrodeposited substrate 1 from the liquid A by lowering the liquid A container 11 as shown in FIG. 5, the holding member 12 is tilted so that the electrodeposited substrate 1 is tilted. I just need.

On the other hand, in either case, when the electrodeposited substrate 1 is held and immersed in the holding member 12 so that the segment electrode arrangement direction is horizontal, the holding member 12 is pulled upward or the liquid A The container 11 may be lowered.

In this way, by performing the separating operation between the electrodeposited substrate 1 and the liquid A in the direction different from the segment electrode arrangement direction = the phosphor dot row, the phosphor particles existing between the phosphor dots, The phosphor particles falling from the phosphor dot can prevent the adjacent dots from being adversely affected. This means that when the separation direction is orthogonal to the segment electrode arrangement direction, adverse effects between adjacent dots can be reduced most.

Effect of the Invention As described above, the present invention electrodeposits phosphor particles by an electrophoresis method using an electrodeposition liquid in which phosphor particles are dispersed on a large number of segment electrodes arranged and formed on an electrodeposition substrate. In such an electrodeposition apparatus, a post-electrodeposition immersion means for immersing the electrodeposited substrate immediately after electrodeposition with a liquid having the same properties as the electrodeposition liquid is provided, and after immersion, the electrodeposition substrate and the liquid The direction of separation of the separating means for separating the electrode is set to a direction different from the direction of arrangement of the segment electrodes on the electrodeposited substrate. In the means, the fluorescent material to be removed is immersed in a liquid having the same properties as the electrodeposition liquid, and thereafter, when the electrodeposited substrate is separated from the liquid, the separation direction is set to a direction different from the segment electrode arrangement direction. Adjacent cells by body particles Adverse effect on the gap electrodes can be prevented as much as possible.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example which is a prerequisite of the present invention, FIG. 2 is a process diagram, FIG. 3 is a cross-sectional view showing a modification thereof, and FIG. FIG. 5 is a cross-sectional view, FIG. 6 is a plan view of an electrodeposited substrate, and FIG. 7 shows another modified example of an example which is a premise of the present invention. FIG. 8 is a cross-sectional view showing still another modified example of the premise of the present invention, FIG. 9 is an exploded perspective view of a general phosphor dot array tube, and FIG. 10 is its cross-sectional view. is there. 1 ... Electrodeposition substrate, 2 ... Segment electrode, 11 ... Immersion means after electrodeposition, 13 ... Electrodeposition liquid, A ... A liquid with the same properties as the electrodeposition liquid

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Ikuo Kato 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company, Ltd. (56) References JP-A-61-203531 (JP, A) JP-A Sho 50-151233 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01J 9/227 C25D 13/00, 13/02

Claims (1)

(57) [Claims] An electrodeposition apparatus in which phosphor particles are electrodeposited by an electrophoresis method using an electrodeposition solution in which phosphor particles are dispersed on a large number of segment electrodes arranged and formed on an electrodeposition substrate. In, provided with a post-electrodeposition immersion means for immersing the electrodeposited substrate immediately after electrodeposition with a liquid having the same properties as the electrodeposition liquid, the separation means for separating the electrodeposited substrate and the liquid after immersion An electrodeposition apparatus characterized in that a separation direction is set to a direction different from a direction in which segment electrodes are arranged on the electrodeposited substrate.