JP3481988B2 - Gas discharge display panel - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas discharge display panel, and more particularly to a color DC type gas discharge display panel,
With a transparent electrode used as a component of a display panel, the change in discharge sustaining voltage with time is suppressed, the change in emission brightness with time is reduced, and the life is extended, and the emission brightness and emission efficiency of the panel itself are improved. Is.

[0002]

2. Description of the Related Art As a conventional example of a color DC discharge display panel, there is a structure shown in FIGS. 23, the cathode 2 is provided on the front glass substrate 1,
Further, both an anode 7 and an auxiliary anode 8 are formed on the rear glass substrate 9 so as to be orthogonal to the cathode 2, and a discharge cell surrounded by a partition wall 3 is formed at each intersection of the anode 7 and the cathode 2. An inert gas is filled in each discharge cell. Briefly explaining the operation of this discharge display panel,
When a specified voltage is applied to a specific cathode 2 and anode 7,
A discharge occurs between them. The phosphor 5 is excited by the ultraviolet rays generated at this time to emit light. In this way, a specific discharge cell (the discharge cell at the intersection of the cathode 2 and the anode 7) in the panel can be made to emit light. This light emission is radiated to the outside through the front glass substrate 1. A full-color image can be displayed by making the phosphor 5 red, green, and blue for each discharge cell. The auxiliary anode 8 is for causing discharge to occur in advance with the cathode 2 and for promoting the start of discharge of the display cell by the priming effect via the slit 4. 24 is the same as that shown in FIG. 23 except that the partition wall parallel to the cathode is removed.

It has been known that in such a discharge display panel, deterioration of luminance with time due to sputtering of the cathode can be prevented if the conditions of high gas pressure and small driving current are satisfied. (For example, Japanese Patent Application No. 3-202135 and Japanese Patent Application No. 3-202135)
(See No. 306247) In order to satisfy this condition in a known constant voltage driving method such as a pulse memory driving method, for example, a resistor-equipped panel having a resistor 11 formed between an anode bus 10 and an anode 7 as shown in FIG. Will be needed. The cathode material of these panels is made of a material such as nickel Ni, aluminum Al, or lanthanum hexaboride LaB ₆ . 23 and 24, a portion indicated by reference numeral 6 forms a bottom surface of each discharge cell and shows a white background to which red, green and blue phosphors are adhered.

[0004]

Problems of the color DC type gas discharge display panel at the present time include deterioration of luminance with time, improvement of light emission high rate, and change of discharge sustaining voltage with time. First, the deterioration with time of the luminance can be solved by using the panel with resistance (FIG. 25) as described above. In addition, regarding the improvement of the luminous efficiency, a method of applying a phosphor to the partition wall or ITO (indium)
-Tin-oxide) and other transparent electrode materials can be used for the cathode to improve the aperture ratio.

However, there has been no good solution to the change in the discharge sustaining voltage with time. As one of the causes of the temporal change of the sustain voltage, it is considered that the discharge area changes due to the sputtering of the cathode. The cathode is Ni or A
When it is formed by thick film printing such as l, the discharge sustaining voltage continues to decrease while oscillating with the vibration of the brightness, and usually decreases by 30 V or more by the half-life of the brightness.

This voltage is lo when the drive time is represented by t.
Since it tends to decrease according to g (1 / t), a method of increasing the pre-aging time of the panel and reducing the voltage in advance before use can be considered. However, this method has a problem in practical use because the luminance is deteriorated and aging takes longer as the panel becomes larger. On the other hand, a method of correcting the drive voltage by a circuit method is also conceivable, but there is a problem such as an enormous circuit scale in order to make an appropriate correction for all the discharge cells. A panel that does not change over time is desired.

Further, with respect to a thin film cathode including a transparent electrode, which is usually used in a thickness of about 200 nm to 500 nm, voltage oscillation occurs, or the voltage changes drastically at a certain point, and the brightness also sharply increases thereafter. There was a phenomenon in which the discharge was stopped and the discharge was stopped, and the cause and solution for this phenomenon had not been found yet.

An object of the present invention is to use a transparent cathode such as ITO, and the discharge sustaining voltage hardly changes with time within a practical period of time, has higher brightness than a conventional gas discharge display panel, and has less deterioration with time of brightness. To provide a panel.

[0009]

In order to achieve the above object, the gas discharge display panel of the present invention has a thickness in contact with a spacer, a partition wall and / or an inner surface of the transparent front plate between the transparent front plate and the rear plate. A plurality of discharge cells arranged in a matrix by an insulator that extends in the direction and partially divides the space, and the bottom surface and / or the side wall of each discharge cell emits visible light of an emission color. In a gas discharge display panel coated with a luminescent phosphor, a cathode made of a transparent electrode material is provided on the inner surface of the transparent front plate for each discharge cell, and the area of the cathode per one discharge cell. When the space between the transparent front plate and the back plate is partitioned by the spacer, the partition and / or the insulator, the transparent front plate is inscribed in the spacer, the partition and / or the insulator. Not less than 80% of the area is photocells occupied, the thickness of the insulator is characterized in that it has more than 5μm in the direction of further said bottom surface from the lower surface position of the cathode.

The present invention is also characterized in that the film thickness T of the cathode is set to a value in the range of T≤2800 nm.

The present invention also relates to He as an enclosed mother gas.
When the gas partial pressure ratio occupies at least 70% of the total enclosed gas pressure, the film thickness T of the cathode is set to a value in the range of 770 nm ≦ T 2.

The present invention also relates to He as an enclosed mother gas.
When the partial pressure ratio of the gas occupies at least 70% of the total enclosed gas pressure, the total enclosed gas pressure is PTorr, the cathode area in each cell is Sμm ² , the discharge current is IμA, and the cathode film thickness is Tnm (S / I) The feature is that the conditional expression of ^2.2 · P ^2.9 · T ≧ 4.1 × 10 ¹⁷ is satisfied.

The present invention is also directed to Ne as an enclosed mother gas.
When the partial pressure ratio of the gas occupies at least 70% of the total enclosed gas pressure, the total enclosed gas pressure is PTorr, the cathode area in each cell is Sμm ² , the discharge current is IμA, and the cathode film thickness is Tnm (S / I) It is characterized in that the conditional expression of ^2.2 · P ^2.9 · T ≧ 1.1 × 10 ¹⁷ is satisfied.

Furthermore, in the present invention, the total of the partial pressure ratios of Ne gas and He gas as the sealed base gas is less than 70% of the total filled gas pressure, the total filled gas pressure is PTorr, and the partial pressure ratio of Ne is N%. The He partial pressure ratio is H%, the cathode area in each cell is S μm ² , the discharge current is I μA, and the cathode film thickness is Tnm.
When

[Equation 2] However, when N% ≦ 10% and / or H% ≦ 10%, N% = 10% and / or H% = 10%, respectively.
It is characterized in that the following conditional expression is satisfied.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. The gas discharge display panel of the present invention has been constructed based on the results of various basic experiments conducted to find out the constitutional conditions of the panel for achieving the object of the invention. The various conditions defined in the claims will be described separately in 5.

Example 1. Conditions relating to the cathode area, which is one of the constituent conditions of the present invention, were also determined from some basic experiments. The front panel (transparent front plate) used in the experiment is shown in Fig. 1.
An ITO cathode as shown by one discharge cell in (a) is formed by sputtering on the inner surface of the front panel made of glass. Here, FIG. 1A is a top view of one discharge cell of FIG. 23 shown as a conventional technique, and reference numerals 2 and 3 are a cathode and a partition, respectively. In the figure, the area occupied by one discharge cell on the front panel is shown by the sum of areas A, B, and C, and the area A is the area of the cathode per one discharge cell.

First, the general structure of the panel in this embodiment will be described. IT formed on the inner surface of the front panel
For the O cathode, its thickness is 200 nm and its resistivity is 1.
It is 6 × 10 ⁻⁴ Ωcm. As the back panel, the back glass substrate 9 shown in FIG. 23 as a conventional technique is used as it is. Here, a white glass material was used for the barrier ribs 3 and the white back 6 of the discharge cell, and an Al paste for thick film printing was used for the anode 7 and the auxiliary anode 8. Regarding the dimensions of each discharge cell, the inner dimensions of the barrier ribs are 450 μm × 600 μ
m, the partition wall has a width of 100 μm and a height of 200 μm. Further, the front panel and the rear panel are joined together using a low-melting glass frit, and helium-xenon (inert gas) He-Xe (10%) was added to each cell space at a gas pressure of 20.
It was sealed at 0 Torr to form a gas discharge display panel.

The width W of the ITO cathode of this panel (see FIG.
The vertical length of the area A in (a), that is, the width of the cathode 2) is W = 490 μm, 190 μm, and 90 μm.
FIG. 2 shows the results of plotting the change in the discharge sustaining voltage when the discharge cell is driven with a constant current of DC at 100 μA every 1 minute instead of m. At this time, there was a large difference in the change over time of the sustain voltage depending on the width of the cathode. Width W
= 490 μm, the sustaining voltage hardly changed until a certain time point, and after that, it showed a remarkable characteristic that it suddenly drastically changed and started to vibrate (hereinafter, this time point is referred to as a voltage fluctuation point). On the other hand, as the width becomes narrower at W = 190 μm and 90 μm, the vibration of the voltage becomes more intense and the clear voltage fluctuation point is not exhibited. In addition, there was a phenomenon that the time until the discharge was stopped was shortened.

In order to investigate the cause, a portion where the phosphor is not printed is provided in the panel, and the width W = 90 μm and 49
It was decided to directly observe the state of discharge at 0 μm. FIG. 3 shows the state at this time. As can be seen from this figure, when the width W = 90 μm, since the width of the cathode is small, the discharge concentrates on the strip-shaped cathode immediately after the start of the discharge, and the discharge part spreads while fluctuating from side to side. As the voltage oscillates, its average value decreases.
After that, the discharge part locally changes and becomes smaller, and then the discharge stops. At the time of this stop, the voltage keeps oscillating and rises.

On the other hand, when the width W is 490 μm, the discharge portion spreads over the entire cathode immediately after the start of discharge, and the spread state does not change until just before the voltage fluctuation point, and the voltage hardly changes during that time. After the voltage change point, the discharge portion alternates between the central portion and the peripheral portion of the discharge cell, and eventually the discharge is stopped.

The change in these voltages is due to the sputtered I
It is generated because TO adheres to the discharge surface of the front glass plate and changes the cathode area. The width W = 490 μm, that is, the areas B, A, and C in FIG. 1A are 24.75 μm ² (55 μm × 450 μm) and 2 respectively.
20.5 μm ² (490 μm × 450 μm), 24.7
From 5 μm ² (55 μm × 450 μm), the ratio of the cathode area A to the front panel area (B + A + C) (called the cathode area ratio), that is, A / (B + A + C) is 80% or more (in this example, about 82%) (Claims)
This corresponds to one component in claim 1), and when 80% or more of the discharge cell is discharged from the beginning, the discharge area is hardly changed and the sustain voltage is stable. Conceivable. It is considered that this is because the ITO attached to the glass surface easily functions as a cathode, but the ITO attached to the partition wall hardly functions as a cathode.

Here, in order to support the above description, the relationship between the sustaining voltage oscillation width and the cathode area ratio in the cell is shown in FIG. 4, and the average sustaining voltage until the sustaining voltage starts rising before the discharge is stopped. FIG. 5 shows the relationship between the change in C and the cathode area ratio.
From both of these figures, it is necessary to set the cathode area ratio to at least 80% or more in order to reduce both the oscillation width of the sustain voltage and the decrease in the average value of the voltage to 5 V or less, which is practical for a gas discharge display panel. . Further, by doing so, the sustain voltage hardly changes up to the voltage fluctuation point, and exhibits a remarkably excellent discharge characteristic as shown in FIG.

Further, widening the cathode area not only reduces the oscillation width of the sustain voltage and the average value of the voltage, but also has the effect of improving the luminance and the luminous efficiency. 60 cells x 6
6 and 7 show the measurement results of the relationship between the average luminance of the entire panel and the luminous efficiency when a 0-cell small panel was driven at a constant current with a duty ratio of 1/60. At this time, for example, when the discharge current I = 100 μA, the width W = 9
At 0 μm, the average luminance and the luminous efficiency are 84 cd each.
/ M ² and 0.23 lm / W, whereas the width W
= 490 μm, 144 cd / m ² and 0.
48 lm / W, brightness is 1.7 times, efficiency is 2.1
Doubled. From the above, such a structure (see FIG. 1 (a))
In the discharge cell of No. 2, it is understood that the efficiency is higher when discharged with a low current density in a wide cathode area than with a high current density in a narrow cathode area. 6 and 7
Shows the measurement results when an Al cathode is used, which will be described next.

Here, the ITO cathode (width W = 490 μm,
In the case of the cathode area ratio = 82%, the thickness 200 nm) and the Al cathode (width W = 1) by the thick film printing which is conventionally used.
The case of 50 μm and thickness 15 μm) will be compared. 1
Each discharge cell was driven at a constant current of DC at 100 μA, and the sustain voltage and the luminance (measured by a photodiode) were plotted every 1 minute, and the results are shown in FIGS. 8A and 8B, respectively. Regarding the sustaining voltage, the Al cathode continues to decrease while vibrating, and decreases to nearly 50 V by the brightness half-life. As for the brightness, when the two are compared up to the voltage fluctuation point, the ITO cathode has less fluctuation because the voltage is stable, and the deterioration is slower. This Al cathode panel has a discharge current I = 60 μA and a current density of 8.8 × 10 ⁻⁴ μA / μ.
Aging was carried out for 2 hours under the condition of m ² and the duty ratio Duty = 1/60. In addition, in FIG.8 (c), the luminous efficiency is also plotted and plotted for every 1 minute.

In thick film printing such as Al, the sustaining voltage is lo
Since it tends to decrease as g (1 / t) (t indicates the passage of time), there is also a method of aging for a long time with a large current to decrease the voltage in advance. However, this method also lowers the brightness and efficiency, and requires a longer panel for a larger panel, which is not preferable in practice. on the other hand,
This ITO panel has a discharge current I = 100 μA, a current density of 4.5 × 10 ⁻⁴ μA / μm ² , and a duty ratio of Duty = 1.
Although the aging was performed for about 10 minutes under the condition of / 60, the sustain voltage hardly changed from the start of discharge to the voltage fluctuation point, indicating that aging is hardly required. As shown in FIGS. 6 and 7, the luminance and luminous efficiency of the ITO cathode are higher than those of the Al cathode in the initial value, and the deterioration with respect to the initial value is slower.

Therefore, in a gas discharge display panel having a cathode area ratio of 80% or more, if the time to the voltage fluctuation point can be extended to the practical range, it is possible to improve all the deterioration of luminance with time and the change of luminous efficiency and sustain voltage with time. Like Therefore, we examined why the voltage fluctuation point occurs.
Regarding this point, from the results of measuring the electrodes before and after the voltage fluctuation point with an EPMA (electron beam microanalyzer) or a stylus type surface profile measuring device, ITO, which is the cathode material, was blown off by sputtering, and the glass substrate (front panel) It was found that the voltage fluctuation point occurred when the exposure started. Therefore, in order to lengthen the time to the voltage fluctuation point, the film thickness T of the cathode is increased, the discharge current I is decreased, or He-
A method of increasing the pressure P of gas such as Xe can be considered. Here, the time to the voltage fluctuation point when one discharge cell constituting the panel is driven by a constant current and direct current is defined as the life L, and the ITO film thickness T, the discharge current I, and the gas pressure P corresponding thereto are set.
The relationships with and are shown in FIGS. 9, 10 and 11, respectively. From this result, the life L is inversely proportional to the 2.2th power of the discharge current I,
It can be seen that they are approximately proportional to the 2.9 power of the gas pressure P and the film thickness T, respectively. This is also confirmed by Example 2 described below and Example 4 described later.

Example 2. An example in which an ITO cathode is formed on the inner surface of the front panel by sputtering as shown in FIG. 1A, instead of the ITO cathode formed by sputtering (Example 1), as shown in FIG. 1B. Will be described.

First, an ITO paste (ESL # 3050) was printed and fired as a cathode 2 on a glass substrate serving as a front panel, and a silver Ag paste for low temperature firing was printed and fired on the cathode bus bar 12 and the electrode lead portion. Further, black insulating glass 13 was printed and baked so as to hide the cathode bus bar 12. This is joined to the same back panel as the conventional one shown in FIG. 23 using a low melting point glass frit, and helium (H
A gas containing e) as a base gas was enclosed. Also in the present embodiment, Embodiment 1. Similarly, it was found that when the cathode area ratio is 80% or more, the discharge voltage hardly changes (5 V or less), and a stable discharge state is obtained. Moreover, a phenomenon in which the voltage drastically changes from a certain point (voltage fluctuation point) also occurred.
The panel thus made will be described in more detail below.

The cell size partitioned by the partition wall is 450 μm.
m × 500 μm, partition wall height of 200 μm, cathode area of 450 μm × 320 μm, cathode area ratio of 80% (since the distance between the insulator and the partition wall is 400 μm, 32
0 μm / 400 μm = 0.8), He-based gas He—Xe (10%), 350 Torr, ITO film thickness T
80 μ for one discharge cell configured as
When the constant current DC drive is performed at A, the sustain voltage, the luminance, and the light emission efficiency are plotted every one minute, and FIG.
As shown in (a), (b) and (c). Further, the time until the voltage fluctuation point when the discharge cells of the same size are driven by a constant current DC is the life L, and IT
The relationships among the O film thickness T, the discharge current I, and the gas pressure P are shown in FIGS. 13, 14 and 15, respectively. Here, when printing an ITO cathode, if it is printed too thick at one time, the electrode will crack when dried and baked. So, print thinly and dry-fire, and repeat this to make the film thickness. Was adjusted. 13, 14 and 15 show that the life L is inversely proportional to the 2.2th power of the discharge current I, and substantially proportional to the 2.9th power of the gas pressure P and the film thickness T, respectively. The result was the same as that of.

Further, the cell size partitioned by the partition wall is 450 μm × 600 μm, the partition wall height is 200 μm, the cathode area is 450 × 300 μm, and the cathode area ratio is 60% (the distance partitioned by the insulator and the partition wall is 500 μm. Three
00 μm / 500 μm = 0.6), the discharge gas of the panel configured to have a filled gas composition thickness of He-Xe (10%), 200 Torr, when a constant current DC drive was performed at 100 μA, the change in sustain voltage was 20 V. And Example 1. The result is in agreement with the result shown in FIG.

After driving this discharge cell until the discharge was stopped, the results of analyzing the distribution of ITO in the cathode portion using EPMA are shown in FIGS. 16 (a) to (c) and (a ') to (a'). c '). From these figures, it was found that tin Sn and indium In were almost completely ejected from the electrode portion by sputtering when the discharge was stopped. In addition, point a shown in FIG.
FIG. 17 shows the result of measuring the surface roughness after discharge up to the point b by the stylus type surface profile measuring device. From Figure 17,
It can be seen that the cathode, which had a film thickness of 800 nm before the discharge, was exposed to the extent that the glass substrate was exposed after the discharge was stopped. In FIG. 17, the insulating glass looks like a partition because the thickness of the insulating glass by printing has a thickness of about 15 μm. Also in this panel, if the cathode area ratio is 80% or more, the sustain voltage hardly changes. It is considered that, among the sputtered ITO, those attached to the glass substrate on the same plane act as a cathode and are easily discharged, but those attached to the partition wall are difficult to act as a cathode.

Therefore, when the cathode area ratio occupies 80% or more and the periphery is surrounded by the partition wall or the insulator, the discharge of the discharge cell does not further spread, and the sustain voltage does not change. In this case, in order for the insulator to act as a wall for blocking the spread of such discharge, it has a thickness of 5 μm or more further downward than the lower surface of the cathode, that is, has a thickness (claims). (Corresponding to one component in claim 1) is required. Therefore, even if a transparent electrode such as ITO is used for the cathode 2, in the case of a panel having no vertical partition as shown in FIG. 24 (conventional view), the discharge spreads in that direction, so that insulation instead of the partition is provided. It is necessary to provide the body as shown in FIG. 1 (b) or (c). Here, it is ideal that the outer circumference of the cathode is surrounded by partition walls or an insulator. As shown in FIG. 23, where slits are provided for arranging the auxiliary anode for the priming effect, even if there is a portion that does not surround the periphery up to about 20%, that does not hinder the effect of the present invention.

Example 1. And 2. Including H
Measurements were performed on various gas discharge display panels using e as a base gas, and finally the following empirical formula was obtained regarding the life. The partial pressure ratio of He gas as the enclosed base gas occupies at least 70% of the total enclosed gas pressure, and the total enclosed gas pressure is PT.
orr, cathode area in each cell is S μm ² , discharge current is I
Letting μA and the thickness of the cathode be Tnm, and letting the time to the voltage fluctuation point be the life L minutes, the relationship between these elements can be expressed by the following equation (1). L = 2.4 × 10 ⁻¹⁴ (S / I) ^2.2 · P ^2.9 · T (1) Here, when actually displaying a color TV on the panel, the normal time rate Duty is about 1/60, The unit minutes of the service life L in the above equation can be directly converted into hours. In order to make the life L when displaying on a color TV display 10,000 hours or more, which is a sufficiently practical value as a display device, the formula (1) defines (S / I) ^2.2. • P ^2.9 · T ≧ 4.1 × 10 ¹⁷ (2) It suffices to satisfy the conditional expression (2). This equation holds regardless of the difference in the cathode forming method such as sputtering or printing and the presence or absence of the cathode bus.

As for the size of one discharge cell of a large-sized panel for color TV display, miniaturization is required. And 2. 450 μm × 6 exemplified in
A small area of about 100 μm or less is required. For example, in the panel having the structure shown in FIG. 23, the height of the barrier rib is 200 μm, and the size of one discharge cell is 450 μm × 49.
0 μm, cathode area ratio 80%, He-Xe (10%), which is often used as the composition and gas pressure of the enclosed gas, 20
In order to satisfy the condition (2), which is a condition formula for accumulating a life of 10,000 hours or more when He is a base gas, when this one cell is driven with a constant current and direct current of 100 μA by setting to 0 Torr, The film thickness is 3800 nm. This is not only difficult in manufacturing, but also reduces the light transmittance. The relationship between the thickness T of actually printed ITO and the transmittance is shown in FIG. According to FIG. 18, when the thickness T is increased, the blue component having a short wavelength is particularly deteriorated. In the case of color display, in order to maintain the white balance, if the brightness of blue decreases, the brightness of red and green must also decrease. FIG. 19 shows the power spectrum (relationship between wavelength and luminance) of the blue phosphor. FIG. 19
FIG. 20 shows the result of calculation of the relationship between the film thickness and the transmittance of the blue phosphor from the power spectrum data of 1. and the film thickness and transmittance data of FIG. Here, in the first embodiment. 7, the width W is 490 μm and the thickness T is 200 n.
The ITO cathode of m has a width W of 150 μm which is normally used.
Drive current of 100μA, which is a normal value, compared to the Al cathode of
In FIG. 2, since the luminous efficiency is about twice as high as that in FIG.
From 0, the value is in the range represented by the following expression (3). T ≦ 2800 nm (3) Therefore, it is preferable to use within the range represented by the formula (3) (as defined by the claim as the formula defining the upper limit of the thickness T of the cathode). If you prioritize the service life, you may use it longer than that. The thinner the film, the better the transmittance, but the shorter the time (life) to the voltage fluctuation point, the more severe the conditions of the enclosed gas pressure P and the discharge current I become.

Experimental Example 3. In order to reduce the film thickness of the cathode, it is necessary to increase the enclosed gas pressure P and reduce the discharge current I in consideration of the life. To meet such conditions,
A gas discharge display panel having the structure shown in FIG. 21 was created. The size of one discharge cell is 450μm × 600μ
m, the height of the partition wall 3 is 200 μm, and the cathode area is 450 μm
× 490 μm, cathode area ratio 80%, enclosed gas composition, pressure He-Xe (10%), 350 Torr, with resistance of about 1 MΩ, black insulating glass 1 covering cathode bus 12
If one cell with a matrix according to No. 3 is viewed, the panel is as shown in FIG. 1 (c).

In FIG. 21, Al is printed without providing the insulating glass 13 at the intersection of the cathode bus bar 12 and the auxiliary anode 8. In this panel, a current of about 100 μA flows when a TV display is performed by a constant voltage pulse memory drive (duty ratio Duty = 1/60).
From the condition of the formula, in order that the life of this panel exceeds 10,000 hours, the thickness T of the cathode becomes 770 nm ≦ T (4) (the lower limit of the thickness T of the cathode when He is the base gas is set to this ( Although the lower limit of the thickness T can be further thinned while maintaining the performance in the case of other mother gas such as Ne, for example, the lower limit of the thickness T can be further reduced by the formula 4).
In this case, it is not limited to the formula (4)), and the thickness of the transparent cathode that is normally used is 200 nm to 500 nm.
It can be seen that a much thicker cathode must be formed. When one discharge cell is actually driven with a constant current with the thickness of the cathode being 1000 nm, as shown in FIG.
The life up to the voltage fluctuation point exceeds 10,000 minutes, and the time rate is Duty
It was confirmed that a life of more than 10,000 hours can be obtained when TV is displayed at = 1/60. Moreover, as can be seen from FIGS. 6 and 7, this panel has improved the brightness and efficiency about twice as much as the panel using the conventional Al cathode or the like.

Example 4. Next, He is used as an enclosed mother gas.
Instead, a gas discharge display panel was constructed using neon Ne and the same experiment was conducted. As a result, the cathode area ratio was the same as He. Also, regarding the life,
It became as follows.

That is, the partial pressure ratio of the Ne gas as the filled base gas occupies at least 70% of the total filled gas pressure, the total filled gas pressure is PTorr, and the cathode area in each cell is S μm.
^{2. When} the discharge current is I μA and the film thickness of the cathode is T nm, and the time to the voltage fluctuation point is the life L minutes, it can be expressed by the following equation (5). L = 9.4 × 10 ^-14 (S / I) ^2.2・ P ^2.9・ T (5)

Here, when the color TV is actually displayed on the panel, the normal time rate Duty is about 1/60, so that the unit minutes of the life L of the above formula is the same as that of the case where the enclosed mother gas is He. Can be converted to.
In order to make the life L displayed on a color TV longer than 10,000 hours, the formula (5) is used to define (S / I) ^2.2 · P ^2.9 · T ≧ 1.1 × defined in claim 5. The condition of 10 ¹⁷ (6) is obtained, and this equation (6) should be satisfied. It should be noted that this formula is established regardless of the difference in the cathode forming method such as sputtering or printing and the presence or absence of the cathode bus. From this result, it is understood that when Ne is used as the base gas, the film thickness T of the cathode does not have to be as thick as He even with a relatively low gas pressure.

Example 5. In addition, H is used as an enclosed mother gas.
The same experiment was conducted on a mixture of e and Ne. As a result, the service life was as follows.

That is, the total of the partial pressure ratios of the Ne gas and the He gas as the enclosed base gas is 70% in the total enclosed gas pressure.
Less than, the total enclosed gas pressure is PTorr and the partial pressure ratio of Ne is N
%, He partial pressure ratio is H%, cathode area in each cell is S μm
^{2. When} the discharge current is I μA and the film thickness of the cathode is T nm, and the time to the voltage fluctuation point is the life L minutes, the following equation (7) is obtained.

[Equation 3] However, when N% ≦ 10% and / or H% ≦ 10%, N% = 10% and / or H% = 10%, respectively.
To

Here, as in the case where the enclosed mother gas is He and Ne, the case of actually displaying a color TV on the panel will be examined. The time ratio Duty is set to about 1/60 and the life when the color TV is displayed. In order to set L to 10,000 hours or more, the formula (7) is used to define the scope of claim 6

[Equation 4] However, when N% ≦ 10% and / or H% ≦ 10%, N% = 10% and / or H% = 10%, respectively.
The following condition is obtained, and it is sufficient to satisfy the formula (8). It should be noted that this formula is established regardless of the difference in the cathode forming method such as sputtering or printing and the presence or absence of the cathode bus.

The gas discharge display panel of the present invention has been described above with respect to the five embodiments. Besides this, Fig. 1
As shown in (d), in order to lower the discharge starting voltage, the material of the cathode having a low discharge starting voltage, such as Al, LaB ₆ , or barium aluminum, is provided at the position 14 of the transparent cathode 2.
BaAl ₄ or lanthanum calcium chromite C
It is possible to reduce the drive voltage by forming ignition dots such as a _0.2 La _0.8 CrO ₃ . Further, instead of ITO, a high resistance cathode material such as tin oxide SnO ₂ can be used to provide the effect of the present invention and the effect of limiting the current. In this case, the resistor 11 may be omitted.

The transparent cathode material that can be used in the present invention is not limited to ITO, but SnO ₂ and zinc oxide Zn.
O, titanium oxide TiO ₂ , cadmium oxide CdO, cadmium stannate Cd ₂ SnO _4, etc. may be contained. At this time, as a method of forming the cathode, there are a sputtering method, a vacuum evaporation method, a spray method, a CVD method, and the like. Also, as the enclosed mother gas, He, Ne, Xe,
A gas such as krypton Kr or argon Ar can be used.

Further, the phosphor is usually Y ₂ O for red.
₃ : Eu, YVO ₄ : Eu, YP _0.65 V _0.35 O ₄ : E
u, YBO ₃ : Eu or (YGa) BO ₃ : Eu, for green, Zn ₂ SiO ₄ : Mn, BaMg ₂ Al ₁₄ O
₂₄ : Eu. Mn or BaAl ₁₂ O ₁₉ : Mn, Y ₂ SiO ₄ : Ce for blue, YP _0.85 V _0.15 O ₄ , BaMg
₂ Al ₁₄ O ₂₄ : Eu or BaMgAl ₁₄ O ₂₃ : Eu is used, respectively. To deposit these phosphors on the bottom surface of the cell, printing, photo-etching method, adhesive method, spray method or the like is used.

For driving the gas discharge display panel of the present invention, either a constant current driving method such as a line sequential driving method, a direct current memory driving method, or a constant voltage driving method such as a pulse memory driving method can be used. .

[0047]

In the prior art, there is no method for preventing the temporal change of the discharge sustaining voltage in the color DC type gas discharge display panel, which has been a serious problem in practical use. In contrast,
According to the present invention described above, it is possible to realize a panel in which the sustain voltage hardly changes for 10,000 hours required for practical use. At the same time, the brightness and luminous efficiency of the panel are about twice as high as those of the conventional panel, and the change in brightness over time is smaller than that of the conventional panel. Therefore, according to the present invention, it is possible to obtain a sufficient effect for putting the color DC type gas discharge display panel into practical use.

[Brief description of drawings]

FIG. 1 shows a plan view of one discharge cell of a gas discharge display panel of the present invention.

FIG. 2 shows changes with time in sustain voltage when the width of the cathode is changed.

FIG. 3 shows the display when the width W of the cathode is 90 μm and 490 μm (however, one discharge cell)
The photograph of the halftone image displayed above shows the state of discharge.

FIG. 4 shows the relationship between the sustaining voltage oscillation width and the cathode area ratio in the cell.

FIG. 5 shows the relationship between the change in average sustain voltage and the cathode area ratio in the cell until the sustain voltage starts rising before the discharge is stopped.

FIG. 6 shows the measurement results of the relationship between the average luminance of the entire panel surface and the discharge current when the cells were driven at a constant current.

FIG. 7 shows the measurement results of the relationship between the luminous efficiency and the discharge current when the cell is driven at a constant current.

FIG. 8 shows changes with time in sustain voltage, luminance, and luminous efficiency when a cell is driven at a constant current, in comparison with a conventional panel.

FIG. 9 shows the relationship between the life of a gas discharge display panel and the cathode film thickness.

FIG. 10 shows the relationship between the life of the gas discharge display panel and the discharge current.

FIG. 11 shows the relationship between the life of a gas discharge display panel and the enclosed gas pressure.

FIG. 12 shows changes with time in sustain voltage, luminance, and luminous efficiency (for Example 2) when the cell was driven at a constant current.

FIG. 13 shows the relationship between the life of the gas discharge display panel and the cathode film thickness (for Example 2).

FIG. 14 shows the relationship between the life of the gas discharge display panel and the discharge current (for Example 2).

FIG. 15 shows the relationship between the life of the gas discharge display panel and the enclosed gas pressure (for Example 2).

FIG. 16 shows the results of analyzing the state of the cathode (metal ITO) before and after discharge using EPMA, with photographs showing the metal structure (including SEM photographs).

FIG. 17 shows the results of measuring the surface roughness on the cathode cross section before and after discharge using a stylus type surface profile measuring apparatus.

FIG. 18 shows the relationship between the thickness of ITO and the light transmittance (for Example 2) corresponding to the wavelength of light.

FIG. 19 shows a power spectrum of a blue phosphor.

FIG. 20 shows the relationship between the transmittance of a blue phosphor and the cathode film thickness.

FIG. 21. Example 3 of the present invention. 3 shows a gas discharge display panel created by.

FIG. 22 shows the relationship between the life of the gas discharge display panel and the discharge current (for Example 3).

FIG. 23 shows a configuration of a conventional gas discharge display panel.

FIG. 24 shows a configuration of a conventional gas discharge display panel.

FIG. 25 shows a configuration of a conventional gas discharge display panel with resistance.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mizuyoshi Gozawa 1-10-11 Kinuta, Setagaya-ku, Tokyo Inside the Broadcasting Research Laboratories of Japan Broadcasting Corporation (56) Reference JP-A-2-223133 (JP, A) JP-A-4-34819 (JP, A) JP-A-5-2993 (JP, A) JP-A-5-166465 (JP, A) JP-A-5-232901 (JP, A) JP-A-5-290745 (JP, A) JP 52-133092 (JP, A) JP 54-13256 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01J 17/06 H01J 17 / 20 H01J 17/49

Claims (6)

(57) [Claims] 1. A spacer between a transparent front plate and a rear plate,
A plurality of discharge cells arranged in a matrix form are formed by an insulator that is in contact with the partition walls and / or the inner surface of the transparent front plate and extends in the thickness direction to partially partition the space, and each discharge cell is formed. In a gas discharge display panel in which a phosphor that emits visible light of a luminescent color is attached to the bottom surface and / or the side wall of each of the discharge cells, a cathode made of a transparent electrode material is provided on the inner surface of the transparent front plate for each discharge cell. The area of the cathode per one discharge cell is such that the space between the transparent front plate and the back plate is the spacer, the partition wall, and / or
Or 80% or more of the area occupied by one discharge cell that is inscribed in the spacer, the barrier ribs and / or the insulator when partitioned by the insulator and occupies the transparent front plate by one discharge cell, and the thickness of the insulator is A gas discharge display panel, further comprising 5 μm or more in a direction from the bottom surface of the cathode to the bottom surface. 2. The gas discharge display panel according to claim 1, wherein the film thickness T of the cathode is set to a value in the range of T ≦ 2800 nm. 3. The gas discharge display panel according to claim 1, wherein the film thickness T of the cathode is 770 nm ≦ T when the partial pressure ratio of He gas as a filling base gas occupies at least 70% of the total filling gas pressure. A gas discharge display panel characterized by being set to a value in the range of. 4. The gas discharge display panel according to claim 1, wherein He is used as a sealed base gas.
When the partial pressure ratio of the gas occupies at least 70% of the total enclosed gas pressure, the total enclosed gas pressure is PTorr, the cathode area in each cell is Sμm ² , the discharge current is IμA, and the cathode film thickness is Tnm (S / I) A gas discharge display panel characterized in that the conditional expression ^2.2 · P ^2.9 · T ≧ 4.1 × 10 ¹⁷ is satisfied. 5. The gas discharge display panel according to claim 1 or 2, wherein the partial pressure ratio of Ne gas as a filled base gas occupies at least 70% of the total filled gas pressure, and the total filled gas pressure is PTorr, in each cell. Is Sμm ² , the discharge current is IμA, and the film thickness of the cathode is Tnm (S / I) ^2.2 · P ^2.9 · T ≧ 1.1 × 10 ¹⁷ A gas discharge display panel characterized by being. 6. The gas discharge display panel according to claim 1 or 2, wherein Ne gas and H as an enclosed mother gas are used.
When the total of the partial pressure ratios of e gas is less than 70% in the total enclosed gas pressure,
Total fill gas pressure is PTorr, Ne partial pressure ratio is N%, He
Where H is the partial pressure ratio, Sμm ² is the cathode area in each cell, IμA is the discharge current, and Tnm is the thickness of the cathode. However, when N% ≦ 10% and / or H% ≦ 10%, N% = 10% and / or H% = 10%, respectively.
A gas discharge display panel characterized in that the following conditional expression is satisfied.