JP3220514B2 - Plasma 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 display having improved luminance and luminous efficiency by optimizing a protective film for preventing deterioration of a phosphor which emits light due to ultraviolet rays from a Penning mixed gas.

[0002]

2. Description of the Related Art Plasma display panels (PDPs)
Is generated by regularly arranging a pair of discharge electrodes (cathode and anode) between two glass plates containing a rare gas mainly composed of neon, and applying a voltage to a discharge cell formed at the intersection of both electrodes. This is a display panel utilizing the discharge light emission phenomenon.

In a plasma display, a Penning mixed gas is sealed in a discharge space in order to start a discharge at a low voltage. In monochrome display, Ne + Xe (0.1
%) Or Ne + Ar (0.1%).

[0004] In order to color a plasma display, a method of exciting and emitting a phosphor by ultraviolet radiation accompanying discharge has been adopted. The sealed gas is mainly He + Xe
(1-2%) Penning mixed gas is used.

[0005] Plasma displays are classified into DC type and AC type according to the structure of their electrodes. The DC type has a structure in which the voltage application electrode is exposed to the discharge space, and the AC type has a structure in which the voltage application electrode is covered with a dielectric layer. The DC type is manufactured using thick film technology, and the AC type is manufactured mainly using thin film technology.

The AC type can be roughly classified into an opposed type, a surface discharge type,
It is divided into barrier electrode type. The AC type is further broadly classified into a transmission type and a reflection type due to a difference in the location of the phosphor.

FIG. 1 shows a basic structure of an opposed type, in which an X electrode 2a and a Y electrode 2b covered with dielectric layers 1a and 1b are crossed on the inner surfaces of a front glass 3a and a back glass plate 3b. It is arranged. A neon or helium mixed gas is sealed in a discharge space 4 formed by the front glass 3a and the back glass plate 3b. On the surfaces of the dielectric layers 1a and 1b, an MgO film 5a resistant to ion bombardment is provided.
5b are formed. A phosphor 6 is provided between the dielectric layer 1a and the MgO film 5a, which emits light when excited by ultraviolet light generated by a neon or helium mixed gas.

In such an opposed type, when an AC voltage exceeding the discharge starting voltage is applied between the X electrode 2a and the Y electrode 2b, a discharge occurs at the intersection of the two electrodes. Ultraviolet radiation of 147 nm is emitted from Xe of a neon or helium mixed gas by discharge of both electrodes. Phosphor 6 due to the emitted ultraviolet light
Are excited to emit light.

At this time, the electrons and ions generated by the discharge move along the electric field and move to the dielectric layers 1a and 1a, respectively.
b is accumulated on the surface. As a result, a wall voltage of the opposite polarity is generated, so that the discharge is completed in a short time.

The electric charges on the surfaces of the dielectric layers 1a and 1b are:
Even if the applied voltage is removed, it remains and is stored as a wall charge.
Discharge is started at a voltage lower by the wall charge. In order to erase the memory, a discharge for erasing the accumulated charge may be performed.

Further, by covering the phosphor 6 with the MgO films 5a and 5b, the phosphor 6 is protected against the impact of ions generated from the anode, so that the deterioration of the phosphor 6 is prevented and the life is extended. It is planned.

FIG. 2 shows a basic structure of a surface discharge type. In this structure, both the X electrode 2a and the Y electrode 2b are disposed on the rear glass plate 3b side. The phosphor 6 is provided on the surface glass 3a side. Thereby, since the phosphor 6 is cut off from the discharge path, there is an advantage that the deterioration of the phosphor 6 due to ion bombardment is small.

FIG. 3 shows a basic structure of a barrier electrode type and a reflection type, in which a lower electrode 2B and a dielectric layer 7b are formed above a rear glass plate 3b.

Above the dielectric layer 7b, a barrier 8 having a height of about 100 μm for preventing optical crosstalk or the like is provided. On top of the dielectric layer 7b and the barrier 8,
Upper electrode 2A, dielectric layer 7a, phosphor 6, and MgO film 5
b is formed.

A phosphor 6 is provided on the surface glass 3a. In the discharge space 4, a Penning mixed gas of He + Xe (1-2%) is sealed.

In such a barrier electrode type, when a driving voltage is applied between the upper electrode 2A and the lower electrode 2B,
A discharge is generated between the upper electrode 2A and the lower electrode 2B to form a plurality of discharge regions.

As a result, the plasma discharge generated inside the discharge space 4 causes 147n from the Xe of the Penning mixed gas.
m ultraviolet rays are emitted. The phosphor 6 is excited by the emitted ultraviolet light to emit light.

In the reflection type, the light emission by the phosphor 6 applied to the front glass 3a is added to the light emission by the phosphor 6 applied to the barrier 8 and the back glass 3b side. Brightness and luminous efficiency.

[0019]

As described above, the above-described various plasma displays employ a structure in which the phosphor 6 is covered with the MgO films 5a and 5b in order to prevent deterioration due to ion bombardment.

Incidentally, since the MgO film has a high absorption loss of the 147 nm ultraviolet ray generated by the Penning mixed gas, it is necessary to make the MgO film thin in order to cause the phosphor 6 to efficiently emit light.

However, if the MgO film is made thin, a problem arises in that the role of protection against ion bombardment and reduction of the plasma ignition voltage due to secondary electron emission of the MgO film cannot be fulfilled.

The present invention has been made in view of such circumstances, and provides a plasma display capable of both protecting a phosphor and improving luminous efficiency, and achieving high luminance and long life. The purpose is to:

[0023]

According to the present invention, in order to achieve the above object, an electrode for externally applying a voltage to at least one of a front glass and a rear glass is provided.
Furthermore, in a plasma display in which a Penning mixed gas is filled in a discharge space formed between the front glass and the rear glass, at least one of the front glass and the rear glass emits fluorescent light emitted by ultraviolet rays from the Penning mixed gas. A body is formed , covering this phosphor
Consists of alkali metal or alkaline earth metal fluoride
A first dielectric film is formed, and on the first dielectric film
A second dielectric film made of MgO is formed .

The present invention also relates to the above plasma display.
The thickness of the first dielectric film is 1000 to 1000
5000 °, and the thickness of the second dielectric film is 100 to
It is characterized in that it is 1000 ° .

[0025]

In the plasma display of the present invention, the phosphor is made of an alkali metal or a dielectric having a low absorption loss of ultraviolet rays.
It is covered with a first dielectric film made of an alkaline earth metal fluoride . Even if this dielectric is formed thicker, the transmittance of ultraviolet rays does not decrease, and the thickness is sufficient. This makes it possible to cope with ion bombardment. Also, the first
High secondary electron emission on the dielectric film, resistant to ion bombardment
By forming the second dielectric film made of MgO,
Complements the decrease in the secondary electron emission ratio due to the first dielectric film
Can be

Then, the thickness of the first dielectric film is set to 1000
And the thickness of the second dielectric film is 100
By setting the thickness of the second dielectric film (MgO
The first dielectric film which does not affect ultraviolet absorption while ensuring sufficient luminous efficiency by effectively reducing the plasma ignition voltage by secondary electron emission while minimizing the absorption loss of ultraviolet light by the film). By increasing the thickness, it is possible to ensure a sufficient protective effect on the phosphor.

[0027]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the drawings described below, portions common to FIG. 3 are denoted by the same reference numerals, and redundant description will be omitted.

FIG. 4 shows an embodiment of the plasma display of the present invention, in which a lower electrode 2B and a dielectric layer 7b are formed on the upper part of a back glass plate 3b.

A barrier 8 is provided above the dielectric layer 7b. An upper electrode 2A, a dielectric layer 7a, and a phosphor 6 are formed above the dielectric layer 7b and the barrier 8.

On the phosphor 6, an MgF ₂ film 10 which is a fluoride of an alkali metal or an alkaline earth metal is provided.
It is formed with a thickness of 00 to 5000 °. This MgF
_{The two} films 10 are transparent films having low absorption loss of ultraviolet rays.
Note that LiF or C is used instead of MgF ₂ which is a fluoride.
Other fluorides such as aF ₂ may be used.

The phosphor 6 is disposed on the surface glass 3a. In the discharge space 4, a Penning mixed gas of He + Xe (1-2%) is sealed.

In such a configuration, when a driving voltage is applied between the upper electrode 2A and the lower electrode 2B, the upper electrode 2A
A discharge occurs between the first electrode and the lower electrode 2B to form a plurality of discharge regions.

As a result, the plasma discharge generated inside the discharge space 4 reduces the Penning mixed gas from Xe to 147n.
m ultraviolet rays are emitted. The emitted ultraviolet light passes through the MgF ₂ film 10 having a low absorption loss and reaches the phosphor 6. The phosphor 6 emits light by receiving ultraviolet rays. Visible light due to light emission is reflected by the phosphor 6 and is seen through the surface glass 3a.

Even if the MgF ₂ film 10 is formed to have a large thickness, the transmittance of ultraviolet rays is less reduced, so that a sufficient thickness can be secured and the phosphor against ion bombardment can be secured. 6 can be sufficiently prevented from being deteriorated.

FIG. 5 shows another embodiment in which the configuration of the plasma display shown in FIG. 4 is changed. A MgO ₂ film 10 having a thickness of 5000 ° is formed on a MgF ₂ film 10 having a thickness of 100 to 1000 °.
An O film 5b is formed.

The secondary electron emission ratio of the MgF ₂ film 10 is M
Since it is low compared to the gO film, thin Mg
By providing the O film, the ratio of secondary electron emission is increased in addition to the reduction of ultraviolet absorption loss, and the plasma ignition voltage is reduced.

FIG. 6 shows another embodiment in which the configuration of the plasma display of FIG. 4 is changed. In this embodiment, a phosphor 6 and an MgF ₂ film 10 are formed on the surface glass 3a side.

FIG. 7 shows another embodiment in which the configuration of the plasma display of FIG. 6 is changed. In this embodiment, MgF is used.
_The MgO film 5a is formed on the upper part of the _second film 10.

As described above, in each of the above-described embodiments, the phosphor 6 is covered with the MgF ₂ film 10 which is a fluoride having a low absorption loss of ultraviolet light, so that the MgF ₂
Even if the film 10 is formed to have a large thickness, the transmittance of ultraviolet rays does not decrease, so that a sufficient thickness can be ensured, and accordingly, it is possible to cope with ion bombardment.

Further, by forming a thin MgO film 5a on the MgF ₂ film 10 having low absorption loss of ultraviolet light,
The luminous efficiency can be improved, and the decrease in the rate of secondary electron emission can be complemented.

[0041]

As described above, in the plasma display of the present invention, the fluorescent material is covered with the dielectric material having low absorption loss of ultraviolet light so that the ultraviolet light can be transmitted even if the dielectric material is formed to be thicker. The ion bombardment can be dealt with without reducing the rate and with a sufficient thickness.

Further, by forming a dielectric material resistant to ion bombardment on the dielectric material having a low absorption loss of ultraviolet light, a reduction in the rate of secondary electron emission by the dielectric material having a low absorption loss of ultraviolet light is complemented. Can be.

As a result, the protection of the phosphor and the improvement of the luminous efficiency can both be achieved, and the higher luminance and the longer life can be achieved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a basic structure of a conventional opposed-type plasma display.

FIG. 2 is a perspective view showing a basic structure of a conventional surface discharge type plasma display.

FIG. 3 is a perspective view showing a basic structure of a conventional barrier electrode type plasma display.

FIG. 4 is a perspective view showing a basic structure of a barrier electrode type plasma display of the present invention.

5 is a perspective view showing another embodiment in which the configuration of the basic structure of the barrier electrode type plasma display of FIG. 4 is changed.

FIG. 6 is a perspective view showing another embodiment in which the configuration of the basic structure of the barrier electrode type plasma display of FIG. 4 is changed.

FIG. 7 is a perspective view showing another embodiment in which the configuration of the basic structure of the barrier electrode type plasma display of FIG. 6 is changed.

[Explanation of symbols]

2A Upper electrode 2B Lower electrode 3a Surface glass 3b Back glass 4 Discharge space 5a, 5b MgO film 6 Phosphor layer 7a, 7b Dielectric film 8 Barrier 10 MgF ₂ film

Claims (2)

(57) [Claims] An electrode for applying a voltage from outside to at least one of a front glass and a rear glass is provided,
Further, in a plasma display in which a discharge space formed between the front glass and the rear glass is filled with a Penning mixed gas, at least one of the front glass and the rear glass is fluoresced by ultraviolet rays from the Penning mixed gas. A body is formed and covers the phosphor with an alkali metal or aluminum.
Forming a first dielectric film made of potassium earth metal fluoride
A second layer made of MgO is formed on the first dielectric film.
A plasma display, wherein a dielectric film is formed . 2. The method according to claim 1, wherein said first dielectric film has a thickness of 1,000 to 1,000.
5000 °, and the thickness of the second dielectric film is 100 to
2. The plasma display according to claim 1, wherein the angle is set to 1000 [deg .].