JPH0990882A - Emissive display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an emissive display element with which the constitution of a lightweight and small-sized plane display having a large display area is possible, discharge current is hardly affected by a working environment, large current is stably obtainable and uniform characteristics and improved durability are obtainable. SOLUTION: This emissive display element has an antiferroelectric substance 2, a front surface electrode 3 and rear surface electrode 4 for impressing AC electric fields on the antiferroelectric substance 2 and a phosphor layer 6 for emitting light by the cold electrons radiated when the alternate electric fields are impressed on the antiferroelectric substance 2. The front surface electrode 3 and rear surface electrode 4 are respectively disposed above and below the antiferroelectric substance 2 and at least one of both electrodes may be a comb-shaped or holed electrode. Glass 7 is disposed in the upper part of the antiferroelectric substance 2. The phosphor layer 6 and the front surface electrode 3 are disposed between the glass 7 and the antiferroelectric substance 2. At least either of vacuum gas, insulator or (n) type semiconductor may be disposed between the antiferroelectric substance 2 and the phosphor layer 6. The cold electron release side of the antiferroelectric substance 2 may be approximately flat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting display device in which cold electrons emitted from an antiferroelectric material are used to cause a phosphor to emit light.

[0002]

2. Description of the Related Art As a display for a man-machine interface with a computer, a flat display such as a liquid crystal display or a plasma display, which is small and easy to use, is often used. As one of the flat panel displays, one using a field emission display element suitable for driving with low power consumption and easily adapted to color display has been studied.

Such a field emission display device is disclosed in, for example, Japanese Patent Laid-Open No. 7-64490, and FIG. 12 shows a typical structure of a cell of the field emission display device. Hereinafter, description will be given with reference to FIG. An insulator substrate 82 is provided in the lower portion of the cell 81, and a lower electrode layer 83, a ferroelectric layer 84, and an upper electrode layer 85 are sequentially laminated on the upper surface of the insulator substrate 82. A glass cell 86 is provided above the cell 81, and a phosphor layer 87 is formed inside the glass cell 86 facing the upper electrode layer 85. In addition, the lower electrode layer 8
A power source 88 is connected to 3, and the upper electrode layer 85 is connected to ground. Further, preferably, a bias electrode 89 is formed between the phosphor layer 87 and the glass cell 86, and a positive bias power source 90 is formed on the bias electrode 89.
Is connected. The inside of the cell 81 is kept in a vacuum state.

In such a cell 81, when an alternating pulse voltage of a predetermined voltage or more is applied to the lower electrode layer 83 by the power source 88, the remanent polarization of the ferroelectric substance is inverted in the ferroelectric layer 84, and this inversion causes the remanent polarization. A strong electric field is generated. When a strong electric field of a predetermined value or more is applied to the ferroelectric layer 84, the electrons in the ferroelectric substance are extracted by the upper electrode layer 85 by the tunnel effect and are emitted to the outside. (This is called a so-called field electron emission phenomenon.) When the phosphor layer 87 is irradiated with the electrons emitted from the upper electrode layer 85, the phosphor emits light.
At this time, when a positive bias voltage of a predetermined value or more is applied to the bias electrode 89, the electrons emitted from the upper electrode layer 85 are accelerated and irradiated on the phosphor layer 87, so that the emission of the phosphor is increased. be able to

With such a structure, it is possible to emit light at a relatively low voltage, and it is possible to reduce the thickness of the laminated body and the size of the cell.
Further, a flat and thin display element can be manufactured. Moreover, color display can be easily achieved by changing the type of the phosphor layer.

Further, Japanese Patent Application Laid-Open No. 7-57620 proposes a field emission display device using a pn junction semiconductor. FIG. 13 shows the structure of the chip portion of such a field emission display device. A chip portion 9 formed in a pyramid shape on the p-type semiconductor substrate 91.
5, a p-type impurity region 92 is formed on the upper surface of the p-type semiconductor substrate 91 including the chip portion 95. An n-type impurity region 93 is formed on the p-type impurity region 92. And the tip portion 9
A shallow junction region 98 is formed of the n-type impurity 93 on the surface portion of 5, and the chip portion 95 itself has a pn junction.

An oxide film 9 having an opening above the p-type semiconductor substrate 91 for oxidizing the surface of the p-type semiconductor substrate 91 around the chip portion 95 and exposing the chip portion 95.
4 is formed, and the oxide film 94 is formed on the oxide film 94.
An insulating film 96 having a pinhole corresponding to the opening is formed. A conductive layer 97 having an opening corresponding to a pinhole of the insulating film 96 is formed on the insulating film 96.

In such a structure, when a reverse bias voltage having a predetermined voltage value is applied to the conductive layer 97 with respect to an electrode (not shown) provided under the p-type semiconductor substrate 91, the p-type chip portion 95 is exposed. Electrons are emitted from the n-junction portion due to the tunnel effect. The field emission electrons can be caused to emit light by irradiating the phosphor layer (not shown) provided on the conductive layer 97 facing the chip portion 95. At this time, the display element section including the chip section 95 and the phosphor layer is held in vacuum.

[0009]

However, the above-described light emitting display device using field emission electrons has the following problems. When a ferroelectric substance is used, in order to efficiently reach the phosphor layer 87 with the emission current, the inside of the cell 81 in which the electron emitting portion and the phosphor layer are arranged is placed in a vacuum state satisfying a predetermined vacuum degree. Must hold. Therefore, there are structural restrictions such as the need for strength for sealing with glass. This is disadvantageous in terms of weight reduction and size reduction in manufacturing a flat panel display having a large display area.

It is also necessary to apply an alternating voltage,
As shown in FIG. 14, an alternating electric field E is formed in the vertical direction of the ferroelectric layer 84.
Is applied, the piezoelectric effect causes mechanical contraction in the direction perpendicular to the electric field and mechanical extension in the parallel direction. Since the upper and lower junctions of the ferroelectric layer 84 are constrained by the upper electrode layer 85 and the lower electrode layer 83, stress is accumulated by the stress inside the ferroelectric layer 84 due to this strain. Therefore, the durability of the ferroelectric layer 84 is reduced and the life of the display element is deteriorated.

Further, as shown in FIG. 15, the remanent polarization Ps remains in the ferroelectric substance even when the applied electric field E returns to zero. However, when the phosphor layer 87 is disposed immediately above the upper electrode layer 85 to form a flat panel display, the phosphor is also a dielectric, so that the remanent polarization Ps of the ferroelectric layer 84 is affected. In response to this, residual polarization also occurs in the phosphor layer 87. This causes problems such as irregular light emission of the phosphor and slow response speed. This is a disadvantage in constructing a flat display that does not use vacuum.

On the other hand, when the pn junction is used, since the emission current is small, the degree of vacuum in the vacuum in which the electron emitting portion and the phosphor layer are disposed and the properties of the trace substances contained in the vacuum ( Hereinafter, the emission current is greatly affected by the vacuum quality). For this reason, it is necessary to hold the display element part in a vacuum satisfying a predetermined degree of vacuum and quality of vacuum.

Further, in order to facilitate the emission of field electrons,
It is necessary to make the discharge part sharp. For this reason, the emission part is formed into a pyramid-shaped chip or a rectangular column-shaped chip. However, such a sharp chip has a small size (in the above-mentioned conventional example, a pyramid-shaped chip with a size of 2 μm). ). However,
In order to form such a minute dimension, it is necessary to use etching such as micromachining, so that the forming process becomes very complicated. As a result, when the display area is increased, it becomes difficult to obtain uniform characteristics of the electron emitting portion.

Also, the sharp portion at the tip of the pyramid-shaped tip portion 95 is easily etched by the positive ions existing in the vacuum to be rounded, so that the emission current becomes small in long-term emission. Furthermore, since the current capacity of the sharp portion of the tip is small, there is a limit to increase the emission current.

The present invention has been made in view of the above-mentioned conventional problems, and it is easy to construct a flat panel display having a large display area in a lightweight and small size, and the emission current influences the operating environment. It is an object of the present invention to provide a light emitting display element that is hard to receive and can stably obtain a large current, and that can achieve uniform characteristics and improved durability.

[0016]

The light emitting display device of the present invention comprises an antiferroelectric material 2, an upper surface electrode 3 and a back surface electrode 4 for applying an alternating electric field to the antiferroelectric material 2, and an antiferroelectric material. 2 is provided with a phosphor layer 6 that emits light by cold electrons emitted when an alternating electric field is applied.

Since the antiferroelectric material is used, even if an alternating electric field of equal magnitude is applied, the polarization becomes larger than that of the ferroelectric material, and the amount of cold electrons emitted at this time is large. Therefore,
The emission current becomes large. Further, since this emission current is not easily affected by the degree of vacuum, etc., a stable emission current can be obtained without using a vacuum. Further, the strain generated in the antiferroelectric substance by the piezoelectric effect due to the alternating electric field extends both in the direction of the electric field and in the direction perpendicular thereto, so that the internal stress of the antiferroelectric substance becomes small and therefore the life is improved. . In addition, since the polarization becomes zero when the applied electric field is zero, even when the flat display is constructed by directly contacting the antiferroelectric substance and the fluorescent substance, the irregular light emission of the fluorescent substance does not occur, and the emission of the fluorescent substance does not occur. Responsiveness is improved.

Since a larger radiation current can be obtained without being affected by the degree of vacuum and the like, the stability of light emission is improved as compared with the case of using the semiconductor of pn junction. Further, since cold electrons are easily radiated from the flat surface of the antiferroelectric material, it is not necessary to form the electron emitting portion into a sharp shape such as a pyramid shape or a square pole shape. Therefore, since the process of forming the display element is simplified, an element having uniform characteristics can be easily obtained, and a large-area display device can be easily manufactured. Further, since electrons are emitted from the flat portion, it is possible to pass a large current, and the shape of the emitting portion does not change even when a current is passed for a long time, and the display stability is improved.

In the above light emitting display device, the upper surface electrode 3 and the back surface electrode 4 are arranged above and below the antiferroelectric body 2, and at least one of the electrodes is a comb-shaped or perforated electrode. Is also good.

With the above structure, when the flat panel display is constructed, the unit display cells are arranged in a matrix in a plane and the upper surface electrodes 3 and the upper and lower surfaces of the antiferroelectric material are provided orthogonally to each other. By selecting the back surface electrode 4 in a matrix and applying an alternating electric field, it becomes easy to emit light at an arbitrary position of the unit display cell. As a result, it becomes easy to configure a flat panel display.

In the light emitting display device, the glass 7 disposed on the antiferroelectric body 2, the phosphor layer 6 disposed between the glass 7 and the antiferroelectric body 2 and the upper surface electrode. 3 and may be provided.

With the above structure, the cold electrons emitted from the antiferroelectric material reach the phosphor layer and cause the phosphor to emit light. This emission is confirmed from the outside of the cell through the glass above the phosphor layer. Therefore, the light emitting display element can be configured with a simple structure.

In the light emitting display element, at least one of vacuum gas, insulator and n-type semiconductor may be provided between the antiferroelectric body 2 and the phosphor layer 6.

When a vacuum gas is used, the cold electrons emitted from the antiferroelectric substance reach the phosphor layer very efficiently, so that the luminous intensity of the phosphor can be increased. When an insulator or an n-type semiconductor is used instead of the vacuum gas, the structure does not need to have a strength for maintaining the degree of vacuum, so that the structure is simple. Furthermore, since the entire display element can be made of a semiconductor, the structure is simple and thin, lightweight and compact.

In the light emitting display device, it is preferable that the cold electron emission side of the antiferroelectric body 2 is substantially flat.

As a result, the current can be increased and the light emission can be easily made bright. Also, the display characteristics are stable even after long-term use.

Further, one or more light emitting display elements may be arranged to form a flat panel display.

With the above structure, a large-area flat panel display having a simple structure and stably obtaining uniform display characteristics can be easily formed.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments and examples of the present invention will be described below with reference to the drawings. FIG.
FIG. 3 is a cross-sectional view of a light emitting display device showing a first example. The light emitting display element 1 is configured based on the antiferroelectric body 2. On the insulating substrate 8, the back surface electrode 4 and the antiferroelectric material 2 are arranged in this order.
And a comb-shaped upper surface electrode 3 is formed. A glass 7 is arranged above the upper surface electrode 3 with a predetermined distance therebetween, and faces the antiferroelectric body 2, and a phosphor layer 6 is formed on the lower surface of the glass 7. Further, in this embodiment, the space between the upper surface electrode 3 and the glass 7 is kept in a vacuum state, and the grid electrode 5 is provided in this space. Then, the back surface electrode 4 is connected to the ground (ground), and the top surface electrode 3 and the back surface electrode 4 are connected.
An alternating power source 9 for applying a positive alternating voltage is connected between the and. Further, a power supply for applying a positive bias voltage is connected to the grid electrode 5, but in the present embodiment, the alternating power supply 9 is also used for connection to the grid electrode 5.

Next, the operation will be described with reference to FIGS. FIG. 2 shows an example of polarization characteristics of the antiferroelectric body 2, FIG. 3 shows an example of an output waveform of the alternating power source 9, and FIG. 4 shows an example of electron emission characteristics of the antiferroelectric body 2. There is. In the display element as described above, when an alternating electric field is applied between the upper surface electrode 3 and the back surface electrode 4 by the alternating power source 9, a periodic electric field between 0 and Emax is applied to the antiferroelectric body 2. Before Emax, there is a switching field S in which the polarization P is rapidly induced by the applied electric field as shown in FIG. While the applied electric field is applied from 0 to the switching field S, electrons are attracted to the upper surface of the antiferroelectric body 2 in the vicinity of the upper surface electrode 3.

At this time, when the polarization is rapidly induced in the switching field S, the attracted electrons repel the polarization, and the antiferroelectric material located in the gap between the comb-shaped upper surface electrodes 3 due to the tunnel effect. Electrons (hereinafter referred to as cold electrons) are emitted from the surface of 2. FIG. 4 shows how cold electrons are rapidly generated, and cold electrons are rapidly emitted in the applied electric field in the vicinity of the switching field S. The emitted cold electrons are accelerated by the grid electrode 5, reach the phosphor layer 6 after passing through the grid electrode 5, and the phosphor layer 6 emits light of a predetermined color. This light emission is recognized from the outside through the glass 7.

After passing the switching field S, the emission of the cold electrons is stopped, and the emission of the cold electrons is stopped until the applied electric field returns to 0 and returns to the vicinity of the switching field S again. When the applied electric field is repeated at a predetermined frequency, the emission and stoppage of emission of the cold electrons are repeated, whereby the phosphor layer 6 repeats light emission and emission stoppage processes. When the frequency of the applied electric field is equal to or higher than a predetermined frequency, there is residual light emission of the phosphor layer 6, so that the human eye recognizes that light emission continues. Therefore, it can be used as a display by controlling the application and non-application of the electric field by an external controller (not shown) or the like.

The antiferroelectric material 2 is, for example, Pb-La.
-Zr-Sn-Ti-O system and Pb-Nb-Zr-Sn-
Ti-O type, Pb-La-Zr-Ti-O type ceramics and the like can be used. In this embodiment, PLZ
"Pb0.97 La0.02 Zr" called ST ceramics
0.66 Sn0.24 Ti0.1O3 "is adopted, and the thickness L2 of this ceramic layer is 30 .mu.m. The polarization characteristic of FIG. 2 shows the characteristic of the adopted PLZST ceramics.

The waveform of the electric field applied to the alternating power source 9 is PL
It is adapted to the polarization characteristics of ZST ceramics. For example, as shown in Fig. 3, when the peak electric field value is 45 KV / cm,
A positive alternating electric field of a triangular wave of Hz was applied. Here, the applied peak electric field value is set by the switching field S of the antiferroelectric body 2. The waveform of the alternating electric field is not limited to the triangular wave, and may be, for example, a rectangular pulse waveform, and the alternating frequency may be several kHz depending on the response of the antiferroelectric material 2.

The upper surface electrode 3 and the back surface electrode 4 are, for example, Pt.
, Au, Ag-Pd, Pd, Al, Cu and the like. The top electrode 3 preferably has a structure so that electrons are easily emitted from the surface of the antiferroelectric body 2 when an alternating electric field is applied between the top electrode 3 and the back electrode 4. Therefore, in this embodiment, the comb-shaped upper surface electrode 3 as shown in FIG. 1 is adopted, but for the above reason, the upper surface electrode 3 is provided with a hole-shaped gap of a predetermined size inside the flat electrode. Such an electrode may be used.

In a flat panel display for displaying characters or figures by dot display, for example, the display cells may be arranged in a matrix in a matrix vertically and horizontally, and each display cell may be accessed and driven in a matrix. Many. In this case, it is preferable that comb-shaped electrodes that specify a matrix are provided above and below the antiferroelectric body 2 so as to be orthogonal to each other, and these electrodes are used as the top surface electrode 3 and the back surface electrode 4. In this embodiment, only the upper surface electrode 3 has a comb shape, and the comb-shaped electrode width L5 is 0.3 mm.

The insulating substrate 8 is made of, for example, Al2O3, Mg.
Although it is composed of O, Si, etc., it may be glass. The phosphor layer 6 is formed on the lower surface of the glass 7 so that the light emission can be seen from the outside when the phosphor layer 6 emits light.
Even if the glass 7 is made of the same insulator as the insulating substrate 8 as described above, the action of light emission by the antiferroelectric material of the present invention does not change.

In this embodiment, one side L as shown in FIG.
The display element 1 is formed on a rectangular insulating substrate 8 of which 1 is 10 mm, and the distance L3 between the upper surface electrode 3 and the grid electrode 5 is L3.
Is 10 mm, and the distance L4 between the grid electrode 5 and the phosphor layer 6 is 5 mm. Thus, the top electrode 3 and the phosphor layer 6 are
Since the distance between them is long, the space between the upper surface electrode 3 and the glass 7 is kept in a vacuum state so that the emitted electrons can easily reach the phosphor layer 6, and the grid electrode 5 is provided in this space. There is. The degree of vacuum of the above-mentioned vacuum may be set to be lower than 10 Pa, and is less affected by the degree of vacuum than in the past.
This is because the cold electrons are emitted from the entire surface of the antiferroelectric body 2 located in the gap between the comb-shaped upper surface electrodes 3.
This is because the emission current becomes large and it is difficult to be affected by the degree of vacuum.

Next, a second embodiment will be described with reference to FIG. FIG. 5 shows a cross section of a unit display cell of the display element 1. In this embodiment, the following intermediate substance 10 is used instead of the vacuum in the first embodiment. For example,
An insulator such as silicon oxide is used with a thickness of several hundred Å or less, or an n-type semiconductor or an inert gas is used. Other configurations are the same as in the first embodiment.

Also in this case, the upper surface electrode 3 is formed in the same manner as described above.
When an alternating electric field is applied between the back electrode 4 and the back electrode 4, cold electrons are emitted from the upper surface of the antiferroelectric body 2. Intermediate material 1
When 0 is an extremely thin insulator, the cold electrons are accelerated by the grid electrode 5 and pass through the insulator having a thickness of several hundred Å or less and reach the phosphor layer 6. In the case of an n-type semiconductor, when the cold electrons are injected, the cold electrons are accelerated by the grid electrode 5 together with the floating electrons inside, and reach the phosphor layer 6. In the case of an inert gas, the cold electrons are similarly accelerated in the inert gas and reach the phosphor layer 6.

As described above, since no vacuum is used, there is no problem such as a complicated structure for maintaining strength so that the glass 7 used for the display surface of the display is not crushed by vacuum. Therefore, it becomes easy to upsize the display. Further, it is possible to configure a very thin display device as compared with the case where a vacuum is used.

The third embodiment will be described with reference to FIG.
FIG. 6 shows a cross section of a unit display cell of the display element 1. On the insulating substrate 8, the back surface electrode 4, the antiferroelectric material 2 and the comb-shaped top surface electrode 3 are formed in this order in the same manner as in the above-mentioned embodiment. A glass 7 is provided above the upper electrode 3 with a predetermined distance.
And the grid electrode 5 is formed on the lower surface of the glass 7. Further, a phosphor layer 6 is formed on the lower surface of the grid electrode 5 so as to face the antiferroelectric body 2. In addition, in this embodiment, the second electrode is provided between the upper electrode 3 and the glass 7.
The same intermediate material 10 as in the example is used. The connection of the alternating power source 9 to each electrode is the same as in the above-described embodiments.

The operation of this embodiment is the same as that of the second embodiment. Also in this case, since the vacuum is not used, it is easy to upsize the display. Further, since the grid electrode 5 is formed between the glass 7 and the phosphor layer 6, the distance between the phosphor layer 6 and the upper surface electrode 3 can be made smaller than that in the second embodiment, and thus a thinner display device is constructed. can do.

A fourth embodiment of the display device 1 shown in FIG.
The unit display cell will be described with reference to the sectional view. In this embodiment, the back surface electrode 4 and the antiferroelectric body 2 are formed in this order on the insulating substrate 8. On the upper surface of the anti-ferroelectric body 2, comb-shaped upper surface electrodes 3 and phosphor layers 6 are alternately formed. That is, the phosphor layer 6 is disposed between the comb-shaped electrodes. Then, the glass 7 is provided on the upper surfaces of the upper surface electrode 3 and the phosphor layer 6.

Similar to the above, the top surface electrode 3 and the back surface electrode 4
When an alternating electric field is applied during, cold electrons are emitted from the upper surface of the antiferroelectric body 2. The cold electrons are immediately irradiated to the phosphor layer 6 on the upper surface, and the emission of the phosphor is confirmed by the glass 7 from the outside. As described above, in this embodiment, since the antiferroelectric substance 2 and the phosphor layer 6 are arranged in contact with each other, there is no intermediate substance 10 as in the previous embodiment, and when the display is constructed, it is very much. It can be made thin. In addition, since a vacuum is not used, it is easy to upsize the display.

The fifth embodiment will be described with reference to FIG.
This embodiment shows an example in which unit display cells are arranged vertically and horizontally to form a flat display, and FIG. 8 shows a cross-sectional view of the display element 1. The back surface electrode 4, the antiferroelectric body 2 and the top surface electrode 3 are formed in this order on the insulating substrate 8, and the back surface electrode 4 and the top surface electrode 3 are comb-shaped electrodes that are orthogonal to each other. For example, as shown in FIG. 8, the comb-shaped electrodes of the back surface electrode 4 are arranged in parallel with the x-axis of the xy plane of the flat panel display, and the comb-shaped electrodes of the upper surface electrode 3 are arranged in parallel with the y-axis. Each unit display cell C is provided with at least one comb-shaped electrode of the back surface electrode 4 and at least one comb-shaped electrode of the upper surface electrode 3. In this embodiment, each unit display cell C is provided with one back surface electrode 4 and two top surface electrodes 3, and a phosphor layer 6 is formed between the two top surface electrodes 3. A hole having a predetermined size may be provided inside the upper surface electrode 3 and the phosphor layer 6 may be formed in this hole.
A glass 7 is provided immediately on the upper surface electrode 3 and the phosphor layer 6. In addition, the upper surface electrode 3 of each adjacent unit display cell C
An intermediate substance 11 is provided between them. This intermediate substance 11
May be made of an insulator (regardless of gas, liquid or solid), air, vacuum or the like.

When an alternating electric field is applied between the upper surface electrode 3 and the rear surface electrode 4 of each unit display cell C, cold electrons are emitted from the upper surface of the antiferroelectric body 2, and the cold electrons immediately illuminate the fluorescence. When the body layer 6 is irradiated, the phosphor emits light. At this time, the alternating electric field is controlled like a matrix between the upper surface electrode 3 and the back surface electrode 4, and the unit display cell C at a predetermined position is controlled.
An alternating electric field is applied so that the LED emits light. That is, for example, the back surface electrode 4 for each unit display cell C is connected to the y-axis electric field controller 15 by power lines y1, y2, y3, etc., and the top electrode 3 for each unit display cell C is controlled for x-axis electric field. Power source lines x1, x2, x3, etc., respectively. The x-axis electric field controller 16 and y
An alternating power source 9 is connected to the axial electric field controller 15.

FIG. 10 shows an embodiment of electric field control of the x-axis electric field controller 16 and the y-axis electric field controller 15. The y-axis electric field controller 15 cyclically powers each power line y at a predetermined cycle.
1, 1, y2, y3, etc. are connected to the alternating power source 9 for a predetermined time. When the power line y1 is connected to the alternating power source 9, x
The axial electric field controller 16 uses the back surface electrode 4 corresponding to the power supply line y1.
Among the unit display cells C11, C21, C31, etc. located above, the power supply line x1 of the upper surface electrode 3 corresponding to the cell to be lit
, X2, x3, etc. are connected to the alternating power source 9. As a result, the alternating electric field is applied only to the cells to be lit, and the cells are lit only for the predetermined time. In this way, the power supply lines x1, x2, x3, etc. corresponding to the cells to be lighted are connected to the alternating power supply 9 in correspondence with the respective power supply lines sequentially connected to the alternating power supply 9, and the predetermined power is supplied in a matrix. The unit display cell C at the position can be made to emit light.

In this embodiment, since the back surface electrode 4 and the top surface electrode 3 are both comb-shaped electrodes and are arranged so as to be orthogonal to each other, each unit display cell is selected in a matrix. It can be displayed arbitrarily. Therefore, it can be configured as a flat panel display capable of displaying characters and figures. Since the antiferroelectric substance 2 and the phosphor layer 6 are disposed in contact with each other as in the previous embodiment, the display is very thin.
Further, when the vacuum is not used, the size of the display is easily increased. If a hole is provided inside the upper electrode 3 and the phosphor layer 6 is formed in this hole, interference of light emission between the unit display cells is reduced.

Next, a sixth embodiment will be described with reference to FIG. FIG. 11 shows a sectional view of the display element 1 when forming a flat panel display as in the fifth embodiment. A back surface electrode 4, an antiferroelectric body 2 and a top surface electrode 3 are sequentially formed on the insulating substrate 8, and the back surface electrode 4 and the top surface electrode 3 are comb-shaped electrodes which are orthogonal to each other as described above. Further, the phosphor layer 6 is formed on the upper surface of the upper electrode 3, and the glass 7 is arranged on the upper surface of the phosphor layer 6. The space between the antiferroelectric substance 2 and the glass 7 may be made of an insulator of the intermediate substance 11 or air, vacuum or the like as in the previous embodiment.

When an alternating electric field is applied between the upper surface electrode 3 and the back surface electrode 4 of each unit display cell C, cold electrons are emitted from the upper surface of the antiferroelectric body 2, and these cold electrons pass through the intermediate substance 11. Then, the phosphor layer 6 is irradiated and the phosphor emits light. At this time, the alternating electric field is controlled in a matrix manner between the upper surface electrode 3 and the rear surface electrode 4 as in the previous embodiment, and the alternating electric field is applied so that the unit display cell C at a predetermined position emits light. . Therefore, it is possible to select and display arbitrary display cells in a matrix, and to configure the display cell as a flat display for characters, figures, and the like.

In the embodiments of the light emitting display device described above, the action of applying an alternating electric field to the antiferroelectric substance to emit cold electrons has been described with reference to the numerical values, but the action and effect of the present invention are described. Is not limited to these numerical values, and the above numerical values are set according to the characteristics of the antiferroelectric material used, or the specifications and performances of the display device to be manufactured. Therefore, it goes without saying that a substance having the same action and effect can be configured within the scope of the present invention by setting other than the above numerical values or by using an antiferroelectric substance having other characteristics.

[0053]

As the antiferroelectric material is used, the emission current can be increased. Moreover, a stable emission current can be obtained without using a vacuum. Moreover, since the internal stress of the antiferroelectric material generated by the piezoelectric effect due to the application of the alternating electric field is small, the life of the display element can be improved. Further, since the polarization becomes zero when the applied electric field is zero, even when the flat panel display is constructed, there is no irregular light emission of the phosphor and the responsiveness of the light emission of the phosphor can be improved. As a result, it is possible to manufacture a bright light-emitting display element that is durable and has excellent display characteristics.

Since it is not necessary to form the cold electron emitting portion by a precise forming process, the forming process of the display element is simplified. Therefore, a device having uniform characteristics can be easily obtained, and a large-area display device can be easily manufactured. Further, since electrons are emitted from the flat surface portion, a large current can be made to flow, and stable display can be obtained even if a current is made to flow for a long time. Therefore, the display performance and reliability can be improved.

When forming a flat panel display, the unit display cells are arranged in a matrix in a plane and the upper surface electrode 3 and the back surface electrode 4 which are orthogonal to each other above and below the antiferroelectric material.
At least one of the electrodes is provided in a comb shape,
An alternating electric field can be applied by selecting both electrodes in a matrix. Therefore, it becomes easy to make any unit display cell of the flat panel display emit light. At this time, if a hole is provided inside the upper electrode 3 and a phosphor layer is formed in this hole, interference of light emission between the unit display cells can be reduced. As a result, it has become possible to easily construct a flat panel display.

The cold electrons emitted from the antiferroelectric material reach the phosphor layer to cause the phosphor to emit light, and this emission can be confirmed from the outside of the cell through the glass above the phosphor layer. Therefore, the light emitting display device can be constructed with a simple structure.

When the vacuum gas is used, the cold electrons emitted from the antiferroelectric substance reach the phosphor layer very efficiently, so that the luminous intensity of the phosphor can be increased. When an insulator or an n-type semiconductor is used instead of the vacuum gas, the structure can be simplified. At this time, since the entire display element can be configured by the semiconductor, the configuration is simplified, and it is possible to easily cope with thinness, light weight and downsizing.

Since the emission current can be increased, the light emission can be brightened. Further, the display characteristics are stable even after long-term use, so that the reliability can be improved.

It has become possible to easily construct a large-area flat panel display having a simple structure and stably obtaining uniform display characteristics.

[Brief description of drawings]

FIG. 1 is a sectional view of a display device according to a first embodiment of the present invention.

FIG. 2 is an electric field-polarization characteristic diagram of an antiferroelectric material for explaining the operation of the first embodiment.

FIG. 3 is a waveform diagram of an alternating electric field for explaining the operation of the first embodiment.

FIG. 4 is an emission charge characteristic diagram of an antiferroelectric material for explaining the operation of the first embodiment.

FIG. 5 is a sectional view of a display element according to a second embodiment of the present invention.

FIG. 6 is a sectional view of a display device according to a third embodiment of the present invention.

FIG. 7 is a sectional view of a display device according to a fourth embodiment of the present invention.

FIG. 8 is a sectional view of a display device according to a fifth embodiment of the present invention.

FIG. 9 is an example of a perforated upper surface electrode according to the fifth embodiment of the present invention.

FIG. 10 is an example of electric field control for explaining the operation of the fifth embodiment of the present invention.

FIG. 11 is a sectional view of a display device according to a sixth embodiment of the present invention.

FIG. 12 is a cross-sectional view of a conventional display device using a ferroelectric material.

FIG. 13 is a cross-sectional view of a conventional display device using a pn junction.

FIG. 14 is an explanatory diagram of internal stress of a display element using a ferroelectric material according to the related art.

FIG. 15 is a field-polarization characteristic diagram of a conventional ferroelectric substance.

[Explanation of symbols]

 1 Light-Emitting Display Element 2 Antiferroelectric Material 3 Top Electrode 4 Backside Electrode 5 Grid Electrode 6 Phosphor Layer 7 Glass 8 Insulating Substrate 9 Alternate Electrode 10 Intermediate Material 11 Intermediate Material 15 y-axis Electric Field Controller 16 x-axis Electric Field Controller 81 Cell 82 insulating substrate 83 lower electrode layer 84 ferroelectric layer 85 upper electrode layer 86 glass cell 87 phosphor layer 88 power supply 89 bias electrode 90 bias power supply 91 p-type semiconductor substrate 92 p-type impurity region 93 n-type impurity region 94 oxide film 95 Chip part 96 Insulating film 97 Conductive layer 98 Junction area Emax Applied maximum electric field value P Polarization S Switching field

Claims (6)

[Claims] 1. An antiferroelectric material (2) and an upper surface electrode for applying an alternating electric field to the antiferroelectric material (2).
(3) and a back electrode (4), and a phosphor layer (6) that emits light by cold electrons emitted when an alternating electric field is applied to the antiferroelectric substance (2). Display element. 2. The upper surface electrode (3) and the back surface electrode (4) are arranged above and below the antiferroelectric material (2), and at least one of the electrodes is a comb-shaped or perforated electrode. The light emitting display element according to claim 1. 3. A glass (7) disposed on the antiferroelectric body (2), and a phosphor layer (6) disposed between the glass (7) and the antiferroelectric body (2). ) And an upper surface electrode (3) are provided, The light emitting display element of Claim 1 or 2 characterized by the above-mentioned. 4. At least one of a vacuum gas, an insulator, and an n-type semiconductor is provided between the antiferroelectric body (2) and the phosphor layer (6). Item 5. The light emitting display device according to item 1, 2 or 3. 5. The cold electron emission side of the antiferroelectric material (2) is
5. It is substantially flat and is characterized by being flat.
The light emitting display device according to item 1. 6. A flat-panel display is constructed by arranging one or more of the light-emitting display elements.
4. The light emitting display device according to 4 or 5.