JP3461454B2 - Plasma address display - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma addressed display device and a method of manufacturing the same.

[0002]

2. Description of the Related Art FIG. 1 shows a structure of a plasma addressed display device, and FIG. 2 shows a sectional view of the plasma addressed display device.
This plasma addressed display device has a flat panel structure in which a display cell 1, a discharge cell 2 and a common intermediate substrate 3 made of a glass sheet having a thickness of 50 μm interposed therebetween are laminated. The display cell 1 is configured by using the upper glass substrate 4, and a plurality of signal electrodes D made of a transparent conductive film are formed on the inner main surface of the display cell 1 in parallel with each other in the column direction. The glass substrate 4 is adhered to the intermediate substrate 3 using a spacer 5 with a predetermined gap. A liquid crystal layer 6 is filled and sealed in the gap.

On the other hand, the discharge cell 2 is constructed by using the lower glass substrate 7. On the inner main surface of the glass substrate 7, anodes A and cathodes K are alternately formed in the discharge channels along the row direction. Further, a partition wall 8 is formed along the top of the anode A. The top of the partition wall 8 is in contact with the intermediate substrate 3 and functions as a spacer.
The lower glass substrate 7 is bonded to the intermediate substrate 3 by using a sealing material 9. An airtightly sealed space is formed between the two. The voids are divided or divided by the barrier ribs 8 to individually configure the discharge channels 10 and serve as row scanning units. That is, the individual discharge channels 10 are connected to the glass substrate 7
A pair of anode electrodes A formed in parallel above, one cathode K formed between them, and a width dimension narrower than that of each anode A and aligned with each anode A. ing. An ionizable gas is enclosed in the airtight discharge channel 10.

FIG. 3 shows an example of a drive circuit used in a display device. This drive circuit is composed of a signal circuit 11, a scanning circuit 12, and a control circuit 13. The signal electrodes D1 to Dm are connected to the signal circuit 11 via buffers. On the other hand, cathodes K1 to Kn are also connected to the scanning circuit 12 via buffers. The anodes A1 to An are commonly grounded. The cathode K is the scanning circuit 12
The signal circuit 11 supplies an analog image signal to each signal electrode D in synchronization with the line sequential scanning.
The control circuit 13 controls synchronization between the signal circuit 11 and the scanning circuit 12. A discharge channel is formed along each cathode K to form a row scanning unit. On the other hand, each signal electrode D serves as a column driving unit. A pixel 14 is defined between both units.

When a DC (negative polarity) drive pulse voltage is applied between the anode A and the cathode K corresponding to the pair of discharge channels, the gas in the pair of discharge channels 10 is selectively ionized. Plasma discharge occurs, and the inside is almost entirely connected to the anode potential. On the other hand, when the plasma discharge ends, the discharge channel becomes a floating potential. An analog signal is written to the sampling capacitor formed of the intermediate substrate 3 of each pixel 14 via the discharge channel to perform sampling and holding. The gradational lighting or extinguishing of the pixel 14 can be controlled by the level of the analog image signal.

In Japanese Patent Laid-Open Publication No. 8-304792, the anode A and the cathode K are not exposed in the discharge channel.
In order to cover the surfaces of the anode A and the cathode K with a dielectric layer, to apply an AC (reverse polarity) drive pulse voltage between both electrodes, and to give a constant potential in the discharge channel at the time of discharge, It is disclosed that the electrodes of the above are installed exposed in the discharge channel. In this structure, the anode A and the cathode K are not exposed in the discharge channel, and writing is performed by the plasma discharge by the AC drive pulse. Therefore, the charge-up of the surface of the dielectric layer covering the anode A and the cathode K is performed. When the discharge is completed, the discharge is stopped in that portion, the discharge is not localized, and a uniform discharge current density can be obtained in the entire discharge channel, and the surfaces of the anode A and the cathode K on the plasma channel side are It has been shown that the plasma discharge makes it difficult to sputter and lowers the transmittance and suppresses the breaking of the electrode.

Japanese Unexamined Patent Publication (Kokai) No. Hei 10-161090 uses an alternating current driven plasma discharge.
This is a modified technique of Japanese Patent No. 792, but since there is no exposed electrode in the discharge channel, a constant potential cannot be applied to the discharge channel. Japanese Patent Laid-Open No. 10-1056
Japanese Patent Laid-Open No. 0-096 discloses that the electrode is covered with a resistance layer to limit the discharge current, thereby improving the life reduction due to sputtering.

[0008]

The structure and manufacturing method of the conventional plasma addressed display device have the following problems.

1. In a plasma addressed display device of the type in which data is written by so-called DC discharge, in which a DC (negative polarity) drive pulse voltage is applied between the anode A and the cathode K to generate plasma discharge inside the discharge channel 10, Since the part where the discharge occurs becomes easier to discharge, the discharge is localized.

Further, due to the voltage drop due to the discharge current,
Discharge is less likely to occur partially. Furthermore, since the cathode is not covered with a dielectric, the metal, etc. that compose the cathode is sputtered and scattered by the ions generated by plasma discharge, and the transmittance is increased between the cathode and the anode or by adhering to the intermediate substrate. Deterioration and change in discharge characteristics occur.

Furthermore, since it is necessary to constantly apply a discharge starting voltage to the cathode, a relatively high voltage must be applied. Further, since the discharge is continued during the drive pulse period, a discharge current flows more than necessary to supply the charged particles to the sampling capacitor made of the intermediate substrate, and the sputtering phenomenon is promoted (FIG. 8).

Further, since the discharge is continued during the driving pulse period, the contrast is lowered by the discharge light emission. Further, when a gas species that emits ultraviolet light is enclosed, the longer the discharge duration is, the more easily organic substances such as the liquid crystal layer on the display cell side are deteriorated by the ultraviolet light.

2. Data is written by so-called AC discharge in which the surfaces of the anode A and the cathode K are covered with a dielectric layer and an AC (reverse polarity) drive pulse voltage is applied between both electrodes to generate plasma discharge inside the discharge channel 10. In a plasma-addressed display device of the type performed, A
Compared with DC discharge, C discharge applies a drive pulse having two voltage levels of positive and negative polarities, so that the cost of a high breakdown voltage drive circuit such as a switching IC is higher.

Further, since the third electrode is installed in the discharge channel, the structure and process are complicated and the cost is high. Further, since the aperture ratio is lowered, the brightness of the plasma addressed display device is lowered.

Further, when the electrodes are stacked in the discharge channel, or when the electrodes are embedded in the partition walls of the discharge channel, the plasma discharge is uniformly performed in the entire channel according to the dimension of the discharge channel. It is difficult to set the optimum electrode spacing to make it work. Moreover, it is difficult to control the stacking with a constant electrode interval and with matching electrode positions, and as a result, a uniform discharge current density cannot be obtained in the entire discharge channel and stable display cannot be obtained in the entire screen.

3. The method of covering the electrodes with a resistance layer to limit the discharge current (for example, described in Japanese Patent Laid-Open No. 10-10560) suppresses electrode spattering by the amount of current limitation, but does not prevent spattering and is basically The above 1. The same problem with is not solved.

The present invention has been made in view of the above circumstances, and an object thereof is to suppress the sputtering of electrodes, prevent a decrease in transmittance and a change in discharge characteristics due to scattering of metal or the like, and stabilize the entire screen. Long life plasma address display device,
It is an object of the present invention to provide a DC discharge type that is simple in driving and structure and can be manufactured at low cost.

[0018]

A plasma address according to the present invention.
The display device scans between two glass substrates facing each other.
In addition to forming a unit discharge channel ,
A liquid crystal is sealed between one of the glass substrates and the third glass substrate, and ions are introduced inside the discharge channel.
Gas and the anode are installed.
And a DC drive pulse between the cathode and the anode.
By applying a voltage, inside the discharge channel
A plasma discharge is generated, and by the plasma discharge,
The voltage applied to the liquid crystal part corresponding to a given pixel is changed.
Then, by rotating the crystal plane of this liquid crystal part,
In the plasma addressed display device for
The cathode in the channel is covered with a dielectric containing a high resistance component.
The dielectric is provided between the cathode and the anode while being covered.
And the cathode and anode are electrically coated with the dielectric.
Is connected to the
It

Electrically connecting the cathode and the anode
The resistance value of the dielectric is preferably 10 to 50 MΩ.
Good

[0020]

The dielectric is a mixture of conductive particles.
It is preferable that it is formed by firing an electric paste.
Yes.

The operation of the present invention will be described below. D
In the case of the C discharge type, the conductor of the electrode is exposed, and a discharge initiation voltage of a relatively high voltage must always be applied to the cathode. Also, the amount of electric current is made to flow more than the purpose of supplying the charged particles to the surface of the thin plate, which promotes electrode sputtering. FIG. 8 schematically shows changes in voltage and current of the DC discharge type.

In order to solve the above problems, in the plasma addressed display device according to the present invention, the cathode is coated with a dielectric or a dielectric containing a high resistance component, and the surface of the dielectric is between the cathode or between the cathode and the anode. And a DC (negative polarity) drive pulse voltage was applied to the cathode so that plasma discharge was generated inside the discharge channel. FIG. 9 shows the drive pulse and the voltage / current change of each part in this case. The surface potential of the dielectric layer on the cathode is the voltage Vp applied to the plasma generation part. When the discharge starts, along with the charge supply to the sampling capacitor composed of the intermediate substrate,
Charged particles are also accumulated on the surface of the dielectric covering the electrodes, and the potential difference between the surfaces of the cathode and the anode, that is, the voltage Vp of the discharge space.
When Vp falls below the discharge sustaining voltage, the discharge stops during the drive pulse period, so the amount of current can be reduced compared to the current structure while maintaining the necessary charge supply to the sampling capacitor composed of the intermediate substrate. Moreover, the sputtering of the electrode is reduced, and it is possible to prevent a decrease in transmittance and a change in discharge characteristics.

When the cathode becomes 0 V, a reverse voltage is induced in the discharge space. When the next pulse arrives, the applied voltage required to start discharge rises due to the remaining charge, so as a countermeasure against this, in order to eliminate the charge on the surface of the dielectric, a high resistance component should be added to the dielectric covering the electrode. Since the electric charges on the dielectric surface are dissipated through the resistance between the dielectric surface and the cathode or the resistance between the anode and the cathode, there is no adverse effect on the discharge by the drive pulse applied to the cathode next. It is estimated that the resistance value for connecting the dielectric surface-cathode or the anode-cathode is preferably 10 to 50 MΩ. For example, 30M
When the anode-cathode is connected with a resistance of Ω, the current flowing through this portion is 0.1 mA, and the charge disappearance time on the dielectric surface is about 1.5 msec, which does not adversely affect the discharge after the next pulse.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A plasma addressed display device can be manufactured by the following steps which are the features of the present invention. FIG. 5 shows a sectional view of the discharge channel portion of the discharge cell in the first embodiment of the present invention. The first embodiment has a structure in which only the cathode is covered with a dielectric containing a highly resistive component.

First, an aluminum film having a thickness of about 2.5 μm is formed on the glass substrate 7 by vapor deposition or sputtering, and then patterned by photoetching or the like to form the anode A.
And the cathode K is formed.

Next, the glass substrate 7 is dipped in an electrolytic solution such as ammonium borate or ammonium adipate, and the cathode K on the glass substrate 7 is used as an anode in the electrolytic solution so that an electric current is passed between the glass substrate 7 and the cathode in the electrolytic solution. The aluminum film surface of the patterned cathode K is oxidized by anodic oxidation to oxidize the aluminum film by means of anodic oxidation to form an alumina film having a thickness of about 1 μm on the surface layer. At this time, the film thickness is about 1.8 μm inside.
The cathode K made of the aluminum film remains.

Since an innumerable number of holes are formed on the surface of the aluminum film when the aluminum film is anodized, the glass substrate 7 having the alumina film formed on the surface of the aluminum film of the patterned cathode K is treated with a metal alkoxide polymer. A solution, for example, a silicon alkoxide or an aluminum alkoxide, ethanol, and water are mixed in a mixed solution having a volume ratio of about 1: 2: 1, and then pulled up, immersed in methanol, washed with water, dried, and then heat-treated at 200 to 250 ° C. for about 1 hour. By filling the pores of the alumina coating with a metal oxide such as silicon or aluminum, the surface of the cathode K made of the aluminum film is integrally coated with the dielectric containing the resistance component made of the alumina film. At this time, the resistance value between the dielectric surface and the surface of the cathode K is 10 to 50 MΩ.
Is.

Further, after the partition wall 8 is formed on the anode A or the glass substrate 7 by a conventional method such as printing or sandblasting, the intermediate substrate 3 made of a dielectric sheet such as thin glass is overlaid, and the peripheral portion is made of low melting point glass or the like. The sealing material 9 is used for airtight joining. Then, an ionizable gas is filled in the discharge channel 10 to complete the discharge cell 2.
Finally, the glass substrate 4 on which the transparent electrodes D, color filters, etc. are formed is laid on the inner main surface of the intermediate substrate 3 via the spacer 5, and liquid crystal is sealed in the gap between the intermediate substrate 3 and the glass substrate 4. Then, the plasma address display device is completed.

FIG. 10 shows a modification of the first embodiment. Dielectric paste containing a high resistance component is printed on the cathode surface, or electrode material is printed on the entire surface.
Subsequently, the dielectric paste or the like is applied by printing at a position substantially corresponding to the cathode, and then the electrode is patterned by sandblasting or the like to cover the surface of the cathode K with a dielectric containing a resistance component.

FIG. 6 shows a sectional view of the discharge channel portion of the discharge cell in the second embodiment of the present invention. The second embodiment has a structure in which the cathode is covered with a dielectric containing a high resistance component and is connected to the anode.

First, the anode A and the cathode K are formed on the glass substrate 7 by a conventional method such as photoetching of a thin film, printing or sandblasting. The cathode K is a dielectric paste containing a high resistance component made by mixing conductive particles in a dielectric paste, for example, printing glass and zinc oxide particles or indium tin oxide particles in a weight ratio of 9: 1. The paste is printed on the cathode K so as to come into contact with the end of the anode A, and subsequently dried at 150 ° C. for about 10 minutes.
The firing is also performed when the partition 8 is formed later,
The surface of the cathode K is covered with a dielectric containing a resistance component so as to come into contact with the end of the anode A, and the resistance value between them is 10 to 50M.
Ω.

Further, after the partition walls 8 are formed on the anode A or the glass substrate 7 by a conventional method such as printing or sandblasting, the intermediate substrate 3 made of a dielectric sheet such as thin glass is overlaid, and the peripheral portion is made of low melting point glass or the like. The sealing material 9 is used for airtight joining.

Thereafter, the discharge channel 10 is filled with an ionizable gas to complete the discharge cell 2. Finally, the glass substrate 4 on which the transparent electrodes D, color filters, etc. are formed is laid on the inner main surface of the intermediate substrate 3 via the spacer 5, and liquid crystal is sealed in the gap between the intermediate substrate 3 and the glass substrate 4. Then, the plasma address display device is completed.

FIG. 7 is a sectional view of the discharge channel portion of the discharge cell in the third embodiment of the present invention. The third embodiment has a structure in which a cathode and an anode coated only with a dielectric are coated with a dielectric containing a high resistance component.

First, the anode A and the cathode K are formed on the glass substrate 7 by a conventional method such as photoetching of a thin film or printing or sandblasting, and the cathode K is printed and coated with a dielectric material such as a glass paste for printing. Next, the anode A and the cathode K coated with a dielectric are mixed with a dielectric paste containing a high-resistance component obtained by mixing conductive particles in a dielectric paste, for example, printing glass and zinc oxide particles or indium tin oxide. The paste is mixed with particles in a weight ratio of 9: 1, for example, and printed on the entire surface of the cathode K and the anode A, and then 150
C. Dry for about 10 minutes. The firing is also performed when the partition 8 is formed later, so that the surfaces of the cathode K and the anode A coated with the dielectric are coated with the dielectric containing the resistance component, and the resistance value between them becomes 10 to 50 MΩ. To

After the partition wall 8 is formed by a conventional method such as printing or sandblasting on the anode A or the glass substrate 7 coated with a dielectric containing a resistance component having a higher resistance,
The intermediate substrate 3 made of a dielectric sheet such as thin glass is overlaid, and the peripheral portion is hermetically joined with a sealing material 9 such as low melting point glass.

Thereafter, the discharge channel 10 is filled with an ionizable gas to complete the discharge cell 2. Finally, the glass substrate 4 on which the transparent electrodes D, color filters, etc. are formed is laid on the inner main surface of the intermediate substrate 3 via the spacer 5, and liquid crystal is sealed in the gap between the intermediate substrate 3 and the glass substrate 4. Then, the plasma address display device is completed.

In the embodiment of the present invention, the cathode K and the anode A are coated with the dielectric and / or the dielectric containing the high resistance component by the anodic oxidation method or the printing method. The present invention is not limited to the above, and any technique that can form a dielectric and a dielectric containing a high-resistance component such as a sol-gel method, a thermal spraying method, a coating method, and a vapor deposition method can be suitably used.

[0040]

As described above, according to the present invention,
In the plasma addressed display device, by covering the cathode with a dielectric or / and a dielectric containing a high resistance component, charged particles are formed on the surface of the dielectric even in DC discharge, which is simpler and cheaper than in the case where the driving circuit is AC discharge. By accumulating, the discharge can be stopped and the discharge current amount can be reduced during the drive pulse period, so that the sputtering of the electrode can be reduced, and the reduction of the transmittance and the change of the discharge characteristic can be prevented. Since the dielectric material covering the cathode is provided with a high resistance component and is in electrical contact with the dielectric surface-cathode or the anode, the dielectric surface-cathode or the cathode-anode is 10
Since they are connected with a resistance of 50 MΩ, the charge on the dielectric surface disappears through the resistance between the dielectric surface and the cathode or the resistance between the anode and the cathode, and does not adversely affect the discharge after the next pulse.

[Brief description of drawings]

FIG. 1 is a schematic exploded view showing the structure of a plasma addressed display device.

FIG. 2 is a schematic cross-sectional view showing the structure of a plasma addressed display device.

3 is a block diagram showing a driving circuit of the plasma addressed display device of FIG.

FIG. 4 is a schematic cross-sectional view for explaining a conventional method for producing a discharge cell.

FIG. 5 is a schematic cross-sectional view for explaining a method for manufacturing a discharge cell in the first embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view for explaining a method of manufacturing a discharge cell in the second embodiment of the present invention.

FIG. 7 is a schematic cross-sectional view for explaining a method of manufacturing a discharge cell in the third embodiment of the present invention.

FIG. 8 is a diagram showing a voltage-current change of a DC discharge type.

FIG. 9 is a diagram showing changes in voltage and current according to the present invention.

FIG. 10 is a schematic cross-sectional view for explaining a method for manufacturing a discharge cell in a modification of the first embodiment of the present invention.

[Explanation of symbols]

1 display cell 2 discharge cells 3 Intermediate board 4, 7 glass substrate 5 spacers 6 liquid crystal 8 partitions 9 Seal material 10 discharge channels 11 Signal circuit 12 scanning circuits 13 Control circuit 14 pixels A anode K cathode D signal electrode

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-4-272635 (JP, A) JP-A-10-221678 (JP, A) JP-A-10-142586 (JP, A) JP-A-6- 251717 (JP, A) JP 10-90664 (JP, A) JP 5-72519 (JP, A) JP 8-68989 (JP, A) JP 5-264979 (JP, A) JP-A-9-171187 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02F 1/1333 G02F 1/1343

Claims (3)

(57) [Claims] 1. A scanning device is provided between two glass substrates facing each other.
In addition to forming a unit discharge channel ,
A liquid crystal is sealed between one of the glass substrates and the third glass substrate, and an ionizable gas is sealed inside the discharge channel.
And a cathode and an anode are provided , and a DC drive pulse voltage is applied between the cathode and the anode.
The plasma discharge inside the discharge channel.
Correspond to a predetermined pixel by generating and plasma discharge
By changing the voltage applied to the liquid crystal part,
Plas that displays by rotating the crystal plane of the part
In the address display device, the cathode in the discharge channel is a dielectric containing a high resistance component.
It is covered with a body and the space between the cathode and the anode is
The cathode and the anode are covered with a dielectric,
Plasma addressed display device characterized by being electrically connected to each other . 2. The cathode and the anode are electrically connected.
The resistance value of the dielectric is 10 to 50 MΩ.
Plasma addressed display device according to. 3. The dielectric material is a mixture of conductive particles.
The method according to claim 1, wherein the dielectric paste is formed by firing.
Plasma address display device .