JP3193749B2 - Plasma 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 plasma display panel (PDP) configured to emit surface light.
It is characterized by the shape of the electrode in plan view.

[0002] PDP is a promising device to be used as a planar light source because it is excellent in brightness and easy to increase in size among flat display devices.

[0003]

2. Description of the Related Art Conventionally, as a PDP configured to generate uniform surface light emission over a relatively wide range, an AC (alternating current) driven PDP of a surface discharge type is known.

FIG. 4 is a plan view schematically showing the electrode structure of a conventional PDP 1j. In the PDP 1j, a comb-shaped discharge electrode Xj including a base portion xa and a number of comb-shaped portions xb;
Similarly, the base ya and the comb-shaped discharge electrodes Yj including a plurality of comb teeth yb are arranged so as to interdigitate with each other.

When a predetermined drive voltage is applied to each of the discharge electrodes Xj and Yj, a discharge cell Cj (two discharge cells in FIG. 3) is interposed between the comb teeth xb and the comb teeth yb adjacent to each other. Cj is representatively shown), and a discharge (surface discharge) occurs in the arrangement direction of the comb-tooth portions xb and yb in each discharge cell Cj. Thus, the light emitting region EH having a predetermined area emits surface light with uniform luminance.

Although it is advantageous to make the line width of the comb-tooth portions xb and yb as small as possible in order to make the luminance uniform, there are various restrictions such as processing accuracy, mechanical strength, and electrical characteristics. Therefore, the thickness is about 100 μm when using the thick film method, and about 50 μm when using the thin film method.

In the PDP 1j, the adjacent comb teeth x
The distance between the b and the comb tooth portion yb (that is, the discharge gap) is
The value is selected to be about 100 to 300 μm suitable for normal glow discharge.

[0008]

The PD having the above-mentioned electrode structure
In P1j, as the light-emitting area EH becomes larger, the comb-tooth portions xb and yb inevitably become longer. That is, each discharge electrode X
Discharge portion of j and Yj (portion defining discharge cell Cj)
Of the individual comb teeth xb, yb increases accordingly.

Therefore, when the light emitting region EH has a size of, for example, 5 inches or more, a spark discharge which causes deterioration or breakage of each portion of the PDP 1j (for example, disconnection of the comb-tooth portions xb and yb) is likely to occur. However, there is a problem that reliability is impaired.

In particular, in order to increase the brightness, the discharge gap is set to about several mm so that the positive column expands, and when an abnormal glow discharge is generated just before transition to the arc discharge, the unit of the electrode is larger than that of the normal glow discharge. Since the discharge current value per length is large, spark discharge is more likely to occur.

The present invention has been made in view of the above problems, and has as its object to realize a large-sized light emitting surface with high reliability.

[0012]

Means for Solving the Problems The P according to the first aspect of the present invention.
DP is configured to uniformly emit light in the entire light emitting region EH by a single pair of electrodes covered with a dielectric layer, and the first and second discharge electrodes X and Y forming the pair of electrodes are formed. Both of the plurality of bus portions Xa and Ya, both of which are parallel to each other, the plurality of branch line portions x and y extending in a form branched from the respective bus portions Xa and Ya, and one end of each of the bus portions Xa and Ya. Are connected to each other, and the branch line portion x of the first discharge electrode X and the branch line portion y of the second discharge electrode Y do not exceed 10 mm from each other.
Parallel and proximate to opposing length, and the branch portions x, y and all other branch portion y adjacent thereto, said first and second discharge electrodes as the discharge occurs between x X and Y are arranged, the discharge gas pressure is set to 300 to 500 Torr,
The distance between adjacent branch lines is determined by the positive column during surface discharge.
Is selected from the range of 1 to 2 mm so as to spread .

[0013]

[0014]

When the light emitting surface is, for example, a square, the light emitting surface is divided into a plurality of regions in the horizontal direction by, for example, generatrix portions Xa, Ya extending in the vertical direction. They will be arranged alternately and parallel to each other.

In each of the discharge electrodes X and Y, the length of each of the branch lines x and y serving as a discharge portion is shorter than the length of each of the divided regions in the horizontal direction, and the number of the bus lines Xa and Ya (that is, the light emitting surface). Can be arbitrarily selected by setting the number of segments.

That is, in the PDP 1, each discharge electrode X,
It is possible to subdivide the discharge part in Y, that is, to shorten the length of the discharge part, thereby reducing the discharge current flowing through each discharge part and suppressing the occurrence of spark discharge.

[0017]

FIG. 1 is a plan view schematically showing an example of the electrode structure of a PDP 1 according to the present invention, and FIG. 2 is a sectional view showing the structure of the PDP 1 in FIG. FIG. 2 shows a cross section taken along the arrow II in FIG.

In FIG. 2, a PDP 1 is a backlight PD having a light emitting area EH of, for example, 5 inches.
P, a pair of glass substrates 11 and 21 facing each other via the discharge space 30, branch lines x and y which are a part of discharge electrodes X and Y described later, a dielectric layer 25 for AC driving, Mg
O protective film 26 and a predetermined emission color (for example, white)
And the like.

The discharge space 30 is filled with a penning gas in which a small amount of xenon is mixed with neon, for example, as a discharge gas. The pressure of the discharge gas is 300-500 Torr (T
orr).

When a predetermined drive voltage is applied to the branch portions x and y as a pair, a discharge (surface discharge) in the direction of the substrate surface occurs between the branch portions x and y, and the phosphor 18 is excited by ultraviolet rays UV due to the discharge. Emits light.

As shown in FIG. 1, the PDP 1 has a pair of discharge electrodes X and Y. Each discharge electrode X, Y
In order to uniformly emit light in the light-emitting region EH indicated by a chain line, the shape in plan view and the positional relationship with each other are selected.

That is, the discharge electrode X is
It is composed of three bus parts Xa extending in the vertical direction, a bus connecting part Xb connecting upper ends of the respective bus parts Xa, and branch parts x extending in the horizontal direction so as to branch off from the respective bus parts Xa at regular intervals. , And a drive circuit (not shown) via an external connection portion Xc.

Similarly, the discharge electrode Y also has three bus portions Ya and a bus connecting portion Y connecting the lower ends of the bus portions Ya.
b, and a branch line portion y extending in a form branched from each bus line portion Ya
And is connected to a drive circuit (not shown) via an external connection portion Yc.

The left end bus line Ya and the right end bus line Xa are provided with branch lines y and x on one side, and the other bus lines Xa and Ya are provided with branch lines x and y on both sides thereof. ing.

The discharge electrodes X and Y have a discharge gap d in which the respective branch portions x and y are about 1 to 2 mm.
Are arranged so as to interlock with each other and to approach each other.

In the PDP 1 having the above-described electrode structure, in comparison with the conventional PDP 1j, the light emitting area EC is subdivided vertically and horizontally to form discharge cells C (FIG. 1 shows four discharge cells C as representatives). ) Is defined. Therefore, the length L of the portion (that is, the discharge portion) related to the definition of each discharge cell C in each of the discharge electrodes X and Y can be a short value of about 1 cm.

In the PDP 1 of this embodiment, as described above, the discharge gap d is 5 to 5 times that of the conventional PDP 1j.
A value of 10 times has been selected. Therefore, high-luminance surface light emission in which the positive column spreads widely in each discharge cell C can be generated, and this effect was actually confirmed by an evaluation test as described below.

In the test, the discharge gap d was set to 1 mm
PDP1 in which a discharge gas mainly composed of neon having a xenon concentration of 10% was sealed at a pressure of 300 Torr, and this was driven by a voltage pulse having a peak value of 250 volts.

As a result, when the driving frequency is 12.5 kilohertz (kHz), a luminance of 970 candela per square meter (cd / m ² ) is obtained, and at that time, the luminous efficiency is 2.48 lumens per watt (lm / m ² ). W). When the drive frequency is 25 kHz, 1600
A brightness of candela per square meter was obtained, at which time the luminous efficiency was 2.09 lumens per watt.

For comparison, a PDP having a discharge gap d of 0.2 mm, which is the same as the conventional one, was manufactured on a trial basis, and when this was driven under the above conditions, when the driving frequency was set to 12.5 kHz, The brightness was 330 candelas per square meter and the luminous efficiency was 0.13 lumens per watt. When the driving frequency was 25 kHz, the luminance was 560 candelas per square meter and the luminous efficiency was 0.11 lumens per watt.

That is, by setting the discharge gap d to a value on the order of millimeters, the luminance is increased approximately three times and the luminous efficiency is increased approximately 20 times as compared with a case where the discharge gap d is selected to be several tenths of a millimeter. Was confirmed.

According to the above-described embodiment, since the discharge gap d is about 1 to 2 mm, high-luminance surface light emission is generated by a driving voltage lower than the withstand voltage of a general driving circuit element, 350 volts. be able to. For example, a luminance of about 3000 candelas per square meter can be obtained by a voltage pulse having a peak value of 250 volts and a frequency of about 45 kilohertz.

According to the above-described embodiment, the bus parts Xa, Ya
The length L of the discharge cell C is arbitrarily set to a short value by appropriately selecting the number of the discharge cells C, and the discharge current flowing through the branch portions x and y defining the discharge cell C is suppressed to prevent the occurrence of spark discharge. Therefore, even if the light emitting area EC is enlarged, the reliability is not impaired.

In the above-described embodiment, the backlight PDP 1 having a single light emitting area EC has been exemplified.
The present invention can also be applied to a segment display type PDP that selectively emits light from a plurality of light emitting areas EC. In that case, a pair of discharge electrodes X, Y
Will be arranged.

In the above-described embodiment, the discharge electrodes X and Y having the bus bars Xa and Ya with the branch lines x and y extending from one point to the left and right are illustrated. However, as shown in FIG. The portions x and y may be provided alternately on the left and right. Further, the extension direction of the branch lines x and y does not necessarily need to be orthogonal to the extension direction of the bus lines Xa and Ya. Other, light emitting area E
The shape of the discharge electrodes X and Y in plan view can be appropriately changed according to the shape and size of C. However, in order to prevent the occurrence of spark discharge, it is desirable that the individual length L of each discharge portion of the discharge electrodes X and Y be 1 cm or less.

According to the present invention, the occurrence of spark discharge which causes deterioration or breakage of each part can be suppressed, and the reliability can be enhanced when the light emitting surface is enlarged. Moreover,
By expanding the positive column, the luminance of surface light emission can be increased.

[0037]

[Brief description of the drawings]

FIG. 1 is a plan view schematically showing an example of an electrode structure of a PDP according to the present invention.

FIG. 2 is a cross-sectional view illustrating a structure of the PDP of FIG.

FIG. 3 is a plan view showing another example of the electrode structure according to the present invention.

FIG. 4 is a plan view schematically showing an electrode structure of a conventional PDP.

[Explanation of symbols]

 1 PDP (Plasma Display Panel) X, Y Discharge electrode Xa, Ya Busbar portion Xb, Yb Busbar connection portion x, y Branch line portion d Discharge gap (distance)

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H01J 11/00

Claims (1)

(57) [Claims] 1. A flat structure in which a single electrode pair covered with a dielectric layer uniformly emits light over the entire light emitting region.
An AC-type plasma display panel for a planar light source , wherein both of the first and second discharge electrodes forming the electrode pair are branched from a plurality of bus portions parallel to each other and each bus portion. A plurality of branch lines extending and parallel to each other, and a bus connecting portion extending so as to connect one end of each of the bus portions; and a branch portion of the first discharge electrode and a branch line of the second discharge electrode. Branch lines are parallel to each other with a length not exceeding 10 mm .
Direction to close, and it is the first and second discharge electrodes are arranged so that the surface discharge occurs between all the other branch portion adjacent thereto and each branch portion, and the discharge gas pressure Between 300 and 500 Torr
The positive column expands the distance between the branch lines
A plasma display panel characterized by being selected from a range of 1 to 2 mm so as to be narrow.