JP2002352738A - Flat display device and drive method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flat display device which has a small power loss, an improved contrast ratio, and a small size. SOLUTION: A data electrode 108 and a cathode electrode in each display cell are arranged facing each other, and discharge is generated only by each needed display cell, by adding a driving pulse in each display cell. Since an insulation layer 104 of a thin film or a fine particle layer is formed on the surface of each cathode electrode 103, the discharge method is a fume-discharge. However, the pulse voltage, added between electrodes arranged facing each other in each display cell, is set higher than the voltage that at which the fume- discharge occurs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a flat display device and a driving method thereof.

[0002]

2. Description of the Related Art In recent years, cold cathode display devices that can be expected to have high luminous efficiency and low power consumption have been developed.

In a cold cathode display device, electrons generated by a cathode are accelerated in a vacuum and applied to a phosphor similarly to a cathode ray tube.
This is a device that excites a phosphor to emit light.

A typical example of a cold cathode that generates electrons is a Spindt-type cold cathode in which a voltage is applied between a conical cathode and a gate electrode surrounding the conical cathode to emit electrons from the sharp tip of the cathode. There is a cathode. Hereinafter, this is referred to as Conventional Technology 1.

The Spindt-type cold cathode according to the prior art 1 has a problem that the electron emission characteristics are unstable. For this reason, when applied as a display device, measures such as forming a large number of minute Spindt-type cold cathodes and averaging the instability of each cold cathode and inserting a resistive layer are taken. ing.

[0006] On the other hand, there is a display device that generates electrons by using a discharge used in a discharge tube or a plasma display panel. Hereinafter, the related art 2 will be referred to.

In the display device according to the prior art 2, a stable supply of electrons can be expected by utilizing discharge.

FIG. 2 shows a display device (Proc.
eedings of the 3 ^rd InternationalDisplay Research C
onference, pp.234-237, 1983).

Referring to FIG. 2, an electron generating section including a cathode 203 for generating electrons and a horizontal electrode 209, and an anode 207 for applying a voltage for accelerating electrons.
And a display unit including a phosphor layer 206.

[0010] The cathode 203 has a width corresponding to a plurality of display cells, and generates a discharge when paired with a scanning electrode (horizontal electrode 209) opposed thereto.

[0011] Here, in order to prevent electrons from colliding with gas atoms and losing energy, the gas pressure of He at a pressure of about 1 Torr, which is lower than that of the plasma display panel, is used.
(Helium gas). In order to cause glow discharge at such a low gas pressure, the distance between the cathode 203 and the anode 207 is set to about 25 mm according to Paschen's law.

Next, the basic operation of the display device will be described.

The cathode 203 has a voltage of -200 V and a horizontal electrode 209.
, A discharge is generated in a line-sequential manner from the upper row of the display device to generate electrons. At this time, if the voltage of the vertical electrode 208 is 0V, the electrons are blocked, and if the voltage is 50V, the electrons pass through the vertical electrode 208.

The electrons passing through the data electrode (vertical electrode 208) are applied to the anode 2 to which a high voltage of about 4 kV is applied.
The light is accelerated by 07 and collides with the phosphor (phosphor layer 206), and the phosphor emits light.

However, this display device cannot operate normally if a discharge occurs between the anode and the data electrode. Therefore, the product of the left side of the Paschen curve, that is, the product of the gas pressure and the distance between the electrodes becomes small. The anode 207 and the vertical electrode 20
8 is set.

[0016]

Here, as described above, in a flat display device of the type in which electrons are accelerated and applied to a phosphor to excite them, it is necessary to accelerate the electrons efficiently. The pressure must be reduced. For this reason, the distance between the cathode 203 and the horizontal electrode 209 for obtaining a stable discharge becomes very large, and the cathode 20
Even if 3 and the horizontal electrodes 209 are arranged in a matrix, it is difficult to control the discharge for each display cell.

Therefore, in this type of display device, regardless of the data signal, a discharge is always generated between the cathode and the horizontal electrode, electrons are extracted when light is emitted, and electrons are cut off when light is not emitted. Apply voltage.

As described above, since the discharge is caused even when there is no signal, the prior art 2 has a problem that the power loss increases.

Further, even in the case of a dark display, there is a problem that a black level is increased and a contrast ratio is deteriorated because discharge is caused.

Further, when the distance between the cathode and the horizontal electrode is large, the size of the electron generating portion becomes large, and there is a problem that the display device cannot be made compact.

Accordingly, the present invention has been made in view of the above problems, and has as its object to provide a miniaturized flat display device and a driving method thereof.

[0022]

According to a first aspect of the present invention, there is provided a flat-panel display device for accelerating electrons generated by a discharge to impinge on a phosphor and exciting the phosphor to emit light. Wherein the cathode surface to which a voltage for generating electrons is applied has an insulator thin film or a fine particle layer.

According to the first aspect of the present invention, the distance between the cathode and the horizontal electrode can be shortened, so that the apparatus can be downsized.

Further, the invention according to claim 2 is characterized in that a cathode and an electrode forming a pair with the cathode are arranged so as to face each display cell.

Thus, according to the second aspect of the present invention, it is not necessary to constantly discharge all the display cells, so that the power loss can be reduced. Furthermore,
Since the light emission in the dark part is suppressed, the contrast ratio can be improved.

Further, the invention according to claim 3 is characterized in that it has an induction electrode to which a pulse for applying generated electrons to a region where an electric field for accelerating the electrons is generated is applied. .

According to the third aspect of the present invention, the generated electrons can be used efficiently,
This makes it possible to provide a flat display device that not only reduces power loss and improves the contrast ratio but also emits a large amount of light.

Further, the invention according to claim 4 is characterized in that it has a shielding electrode for suppressing the bias of the electric field in a region where an electric field for accelerating electrons is generated.

According to the fourth aspect of the present invention, it is possible to suppress image disturbance due to abnormal discharge in the electron accelerator.

According to a fifth aspect of the present invention, there is provided a method of driving a flat display device in which electrons generated by discharge are accelerated and applied to a phosphor to excite the phosphor to emit light. A pulse for generating electrons is applied to the cathode on which the thin film or the fine particle layer is formed to generate field electron emission.

According to the fifth aspect of the present invention, the distance between the cathode and the horizontal electrode can be shortened, so that the apparatus can be downsized.

Further, the invention according to claim 6 is characterized in that a pulse for generating field electron emission is applied to each display cell between a cathode arranged so as to face each display cell and an electrode forming a pair with the cathode. Features.

Thus, according to the present invention, it is not necessary to discharge all the display cells at all times, so that the power loss can be reduced. Furthermore,
Since the light emission in the dark part is suppressed, the contrast ratio can be improved.

Furthermore, the invention according to claim 7 is characterized in that the difference between the potential of the pulse applied to the cathode and the potential of the pulse applied to the electrode paired with the cathode is equal to or higher than the voltage value at which electron generation occurs. And

Thus, according to the seventh aspect of the present invention, electrons can be generated in the thin film or the fine particle layer provided on the cathode, and the distance between the cathode and the horizontal electrode can be shortened.

Further, the invention according to claim 8 is characterized in that a pulse for drawing generated electrons is applied to an electrode provided in a region where an electric field for accelerating electrons is generated. .

Thus, in the invention according to claim 8, since the generated electrons can be used efficiently,
This makes it possible to provide a flat display device that not only reduces power loss and improves the contrast ratio but also emits a large amount of light.

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Features of the present invention] The present invention relates to a device for accelerating electrons generated by a discharge to impinge on a phosphor to emit light, and to perform spray discharge using a cathode having an insulating film. The present invention relates to a structure and a driving method of a display device, wherein the display device is controlled for each display cell and is used as an electron source.

According to this feature, the present invention provides a display device in which electrons generated by electric discharge are used as an electron source, the electrons are accelerated by an electric field to impinge on the phosphor, and the phosphor is excited to emit light. By using a spray discharge that forms a thin insulator layer and emits field electrons as an electron source,
It is possible to reduce the distance between the electrodes causing the discharge, and as a result, the spray discharge is controlled at the intersections of the electrodes arranged in a matrix, so that the generation of electrons can be controlled for each display cell.

Hereinafter, preferred embodiments of the flat display device having the above-described features and the driving method thereof according to the present invention will be described in detail with reference to the drawings.

[First Embodiment] A first embodiment of the present invention will be described below.

Structure of Flat Display Device FIG. 1 is a diagram showing the layer structure of the flat display device according to the present embodiment.

Referring to FIG. 1, the flat panel display according to the present embodiment includes a back plate 101, a center sheet 105, and a front plate 102, the periphery of which is sealed with a frit, and A rare gas is sealed.

The cathode 103 (..., C _j−1 ,
C _j , C _{j + 1} ,...) Are formed as linear electrodes in the row direction. Further, on the cathode 103, an insulator layer 104 necessary for performing a spray discharge is formed.

Here, the insulator layer 104 is made of Al ₂ O ₃ ,
It is formed of a thin film or fine particles of CeO ₂ , ZrO ₂ , MgO, Y ₂ O ₃ or the like. The thickness of the insulator layer 104 is
It is about 0.01 to 1 μm.

On the other hand, on the center sheet 105, the data electrode 108 is provided on the side facing the cathode 103.
(..., _Di-1 , _Di , _{Di + 1} , ...) are formed as linear electrodes in the column direction.

In this configuration, by applying a voltage between the cathode 103 and the data electrode 108, a spray discharge is caused to generate electrons.

The center sheet 105 and the data electrode 108 are provided with an electron extraction hole 109 for each display cell, and are generated by an electron generation unit formed between the cathode 103 and the data electrode 108. Electrons pass through the electron extraction hole 109, and the data electrode 108 and the anode 107
Is configured to be guided to the electron accelerating unit formed between.

Here, each linear electrode of the cathode 103 and the data electrode 108 is formed so as to correspond one-to-one to the row and column line of the display cell.

On the front plate 102, a phosphor layer 106 as a light emitting source is formed on the side facing the center sheet 105, and a voltage for accelerating electrons is provided on the phosphor layer 106. Is applied to form an anode 107.

The phosphor layer 106 is made of P2 for CRT.
2 (Y ₂ O ₂ S: Eu (red), ZnS: Cu,
Al (green), ZnS: Ag (blue), etc. are used.

The anode 107 formed on the phosphor layer 106 is formed by a metal back using aluminum or the like. When the electrons accelerated by the electron accelerator pass through the anode 107 and enter the phosphor, light emission occurs.

Here, the sealed space between the front plate 102 and the back plate 101 is evacuated once,
A rare gas such as e or Ne is sealed at a gas pressure of about 1 Torr.

Driving Method of Flat Panel Display Next, a driving method of the flat panel display shown in FIG. 1 will be described in detail with reference to FIG.

In describing FIG. 3, the voltage at which the spray discharge can occur is assumed to be Vs. Here, the cathode 103
(…, C _j−1 , C _j , C _{j + 1} ,...)
A scan pulse 307 having a voltage of / 2 is applied, and a write pulse 305 of a voltage of Vs / 2 is applied to the data electrodes 108 (..., _Di-1 , _Di , _{Di + 1} ...) in accordance with video data to be displayed. Is applied. At this time, a spray discharge occurs in the display cell to which each pulse is simultaneously applied to the cathode 103 and the data electrode 108 to generate electrons.

Further, a high voltage of several kV is constantly applied to the anode 107 of the front plate 102 in order to accelerate electrons incident on the electron accelerating portion.

Therefore, the electrons generated by the electron generation unit in accordance with the video data pass through the data electrodes 108 and the electron extraction holes 109 formed in the center sheet 105 and enter the electron acceleration unit. To excite the phosphor to emit light.

[Second Embodiment] A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 is a diagram showing the layer structure of the flat display device according to the present embodiment.

Referring to FIG. 4, the flat display device according to the present embodiment is different from the flat display device according to the first embodiment shown in FIG. 1 in that the center sheet 405 (the center sheet 105 in FIG. Anode 40 in correspondence)
7 (corresponding to the anode 107 in FIG. 1) (the side opposite to the side on which the data electrode 408 is formed)
Row electrode 40 parallel to (corresponding to cathode 103 in FIG. 1)
9 is newly formed, and a row electrode 409 and an anode 407 are further formed.
A mesh-shaped shielding electrode 410 is newly formed in a space (electron accelerating portion) between.

In this configuration, the cathode 4 is connected to the row electrode 409.
By giving a potential to allow electrons to pass in synchronization with 03, electrons generated by the electron generation unit between the cathode 403 and the data electrode 408 can be more accurately guided to the electron acceleration unit. .

Further, the shielding electrode 410 is provided to suppress the electric field concentration on the surface of the center sheet 405 and prevent abnormal discharge in the electron accelerating portion.

However, in the above configuration, the data electrode 40
8 and the center sheet 405 are provided with electron extraction holes 411 for each display cell. Furthermore, the shielding electrode 41
0 has a mesh structure that transmits electrons and suppresses the bias of the electric field on the center sheet 405 surface.

Driving Method of Flat Display Device Next, a driving method of the flat display device shown in FIG. 4 will be described in detail with reference to FIG.

In describing FIG. 5, the voltage at which the spray discharge can occur is assumed to be Vs. Here, the cathode 403
(…, C _j−1 , C _j , C _{j + 1} ,...)
/ 2 is applied to the data electrode 408 (..., _Di−1 , _Di , _{Di + 1} ...) According to the video data to be displayed. Is applied. At this time, a spray discharge occurs in a display cell to which each pulse is simultaneously applied to the cathode 403 and the data electrode 408 to generate electrons.

As described above, in synchronization with the scanning pulse 507 applied to the cathode 403, the row electrodes 409 are provided with the electron extraction holes 41 for the electrons generated by the spray discharge.
An auxiliary pulse 508 for assisting the passage of No. 1 is applied. In the present embodiment, the voltage value of the auxiliary pulse 508 is set to Vt. However, the voltage value of the auxiliary pulse is desirably lower than the voltage value of the write pulse 507. Alternatively, it is desirable that the voltage value is such that it does not unnecessarily affect the electron generation unit. This is to prevent the occurrence of spray discharge due to the auxiliary pulse 508 and the scanning pulse 507.

Here, the cathode 403 (..., C_j-1,
C_j, C_{j + 1},...) Sequentially scanning at a voltage of −Vs / 2
A pulse 507 is applied, and a row electrode 409 (..., E
_j-1, E _j, E_{j + 1},...)
8 and the data electrodes 108 (..., D_i-1,
D_i, D_{i + 1}, ...) according to the video data to be displayed
A write pulse 505 having a voltage of Vs / 2 is applied. this
At this time, each pulse is simultaneously applied to the cathode 403 and the data electrode 408.
Spray discharge occurs in the display cell applied to the
And the passing rate of the generated electrons through the electron extraction hole 411.
Is increased by the auxiliary pulse 508.

Further, a high voltage of several kV is constantly applied to the anode 407 of the front plate 402 in order to accelerate electrons incident on the electron accelerating portion. The shielding electrode 410 is connected to the anode 4
Appropriate voltage is applied according to the position between 07 and the row voltage 409. This is, for example, in the case where it is positioned between the anode 407 and the row electrode 409, an intermediate potential between the anode 407 and the row voltage 409 is applied.
Thereby, the concentration of the electric field due to the shape of the row electrode is reduced, and it is possible to suppress the disturbance of the image due to the abnormal discharge in the electron accelerator.

Therefore, the electrons generated by the electron generation unit according to the video data pass through the data electrodes 408 and the electron extraction holes 411 formed in the center sheet 405 and enter the electron acceleration unit. Then, the light is transmitted through the anode 407 and enters the phosphor layer 406 to excite the phosphor to emit light.

[Summary] As described above, the flat display device of each embodiment according to the present invention has a structure in which a glow discharge is conventionally used for electron generation, but a thin insulator layer is formed on a metal. And a structure using spray discharge.

In the spray discharge, a high electric field is induced between the positive charge accumulated in the insulator layer and the cathode, and it is considered that this electric field causes electron emission. In the present invention, the distance between the cathode and the horizontal electrode can be set to an arbitrary value that is smaller than the conventional one.

As a result, according to the present invention, it is possible to form a cathode and a horizontal electrode in a matrix and control the spray discharge for each display cell. In addition, the size of the electron generation unit can be reduced, and the entire display device can be reduced in size.

The embodiments described above are merely examples of preferred embodiments of the present invention, and the present invention can be variously modified and implemented without departing from the gist thereof. It is.

[0074]

As described above, in the conventional system using the glow discharge, the size of the electron generating portion is increased in the flat display device in which electrons are accelerated to excite the phosphor, and the electrodes are formed in a matrix. Although it was not possible to generate electrons for each display cell by arranging them in each of the display cells, in each of the embodiments of the present invention, since this was configured as a cathode that performs spray discharge, the size of the electron generation unit was reduced, and It is possible to control the generation of electrons for each display cell, and it is possible to suppress power loss, which was a problem, by constantly discharging. In addition, this makes it possible to suppress light emission in a dark part, and to improve a contrast ratio. In addition, the size of the electron generation unit can be reduced, so that the device can be made compact.

That is, the invention according to claim 1 is a flat panel display device in which electrons generated by discharge are accelerated and applied to a phosphor to excite the phosphor to emit light, and a voltage for generating electrons is provided. Is characterized in that the surface of the cathode to which is applied has a thin film of an insulator or a fine particle layer, the distance between the cathode and the horizontal electrode can be shortened, and the device can be downsized.

Further, the invention according to claim 2 is characterized in that a cathode and an electrode forming a pair with the cathode are arranged so as to be opposed to each other for each display cell. There is no need to discharge, and power loss can be reduced. Further, since the light emission in the dark part is suppressed, the contrast ratio can be improved.

Further, the invention according to claim 3 is characterized in that it has an induction electrode to which a pulse for applying generated electrons to a region where an electric field for accelerating the electrons is generated is applied. Therefore, it is possible to efficiently use the generated electrons, to reduce the power loss, to improve the contrast ratio, and to provide a flat display device with a large amount of light emission. Become.

Further, the invention according to claim 4 is characterized by having a shielding electrode for suppressing the bias of the electric field in a region where an electric field for accelerating electrons is generated, so that an abnormal discharge in the electron accelerating portion is achieved. It is possible to suppress the disturbance of the image due to.

According to a fifth aspect of the present invention, there is provided a driving method of a flat panel display device in which electrons generated by discharge are accelerated and applied to a phosphor to excite the phosphor to emit light. It is characterized in that a pulse for generating electrons is applied to the cathode on which the thin film or the fine particle layer is formed to generate field electron emission, so that the distance between the cathode and the horizontal electrode can be shortened. Can be reduced in size.

Further, the invention according to claim 6 is characterized in that a pulse for generating field electron emission is applied to each display cell between a cathode disposed opposite to each display cell and an electrode forming a pair with the cathode. Because of this feature, it is not necessary to constantly discharge all display cells, and power loss can be reduced. Further, since the light emission in the dark part is suppressed, the contrast ratio can be improved.

Further, the invention according to claim 7 is characterized in that the difference between the potential of the pulse applied to the cathode and the potential of the pulse applied to the electrode forming a pair with the cathode is not less than a voltage value at which electron generation occurs. Accordingly, electrons can be generated in the thin film or the fine particle layer provided on the cathode, and the distance between the cathode and the horizontal electrode can be shortened.

Further, the invention according to claim 8 is characterized in that a pulse for drawing generated electrons is applied to an electrode provided in a region where an electric field for accelerating electrons is generated. Therefore, it is possible to efficiently use the generated electrons, so that it is possible to provide a flat-panel display device which not only reduces power loss and further improves the contrast ratio but also emits a large amount of light. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a structural view showing a flat display device using a spray discharge according to a first embodiment of the present invention.

FIG. 2 is a structural diagram showing an example of a display device using glow discharge according to the related art.

FIG. 3 is a timing chart showing each pulse for driving the flat panel display according to the first embodiment of the present invention.

FIG. 4 is a structural view showing a flat display device using a spray discharge according to a second embodiment of the present invention.

FIG. 5 is a timing chart showing each pulse for driving the flat panel display according to the second embodiment of the present invention.

[Explanation of symbols]

 101, 401 Back plate 102, 402 Front plate 103, 203, 403 Cathode 104, 404 Insulator layer 105, 205, 405 Center sheet 106, 206, 406 Phosphor layer 107, 207, 407 Anode 108, 408 Data electrode 109, 204, 411 Electron extraction hole 201 Glass container 202 Gas discharge 208 Vertical electrode 209 Horizontal electrode 210 Spacer 305, 505 Write pulse 307, 507 Scan pulse 409 Row electrode 410 Shield electrode 508 Auxiliary pulse

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification FI theme coat ゛ (Reference) H04N 5/68 G09G 3/28 H (72) Inventor Mizuyoshi Gozawa 1-10 Kinuta, Setagaya-ku, Tokyo 11 Japan Broadcasting Corporation Broadcasting Research Institute (72) Inventor Satoshi Ueda 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Research Institute (72) Inventor Tatsuya Takei 1-kinuta, Setagaya-ku, Tokyo No. 10-11 Japan Broadcasting Corporation Broadcasting Research Institute (72) Inventor Hiroshi Hagiwara 1-11-11 Kinuta, Setagaya-ku Tokyo 1-10-11 Japan Broadcasting Corporation Japan Broadcasting Research Institute F term (reference) 5C031 DD17 5C040 FA10 GB20 LA18 MA18 MA19 5C058 AA18 BA26 CA14 5C080 AA03 BB05 DD26 DD30 EE29 FF12 JJ0 4 JJ06

Claims (8)

[Claims] 1. A flat panel display device for accelerating electrons generated by a discharge and applying the electrons to a phosphor to excite the phosphor to emit light, wherein a cathode surface to which a voltage for generating the electrons is applied is applied. ,
A flat display device comprising an insulator thin film or a fine particle layer. 2. The flat display device according to claim 1, wherein the cathode and an electrode forming a pair with the cathode are arranged so as to face each display cell. 3. The device according to claim 1, further comprising an induction electrode to which a pulse for applying the generated electrons to a region where an electric field for accelerating the electrons is generated is applied. Flat display device. 4. The flat panel display according to claim 1, further comprising a shielding electrode for suppressing electric field bias in a region where an electric field for accelerating electrons is generated. apparatus. 5. A method for driving a flat panel display device in which electrons generated by discharge are accelerated and applied to a phosphor to excite the phosphor to emit light, wherein a thin film of an insulator or a fine particle layer is formed on the surface. To the cathode
A method for driving a flat display device, characterized in that a pulse for generating the electrons is applied to cause field emission. 6. A pulse for generating the field electron emission for each of the display cells is applied to the cathode disposed opposite to each of the display cells and an electrode forming a pair with the cathode. Item 6. A method for driving a flat display device according to item 5. 7. The method according to claim 6, wherein a difference between a potential of a pulse applied to the cathode and a potential of a pulse applied to an electrode forming a pair with the cathode is equal to or more than a voltage value at which the electron generation occurs. A driving method of the flat panel display device according to the above. 8. A pulse for attracting the generated electrons is applied to an electrode provided in a region where an electric field for accelerating the electrons is generated.
8. The method for driving a flat panel display device according to any one of items 1 to 7.