JP2003187706A - Plasma display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a panel structure of a plasma display panel whose quality does not deteriorate even when it is used at a high altitude. <P>SOLUTION: In the plasma display panel comprising a pair of substrates arranged in an opposite manner so as to form a discharge space between them and a plurality of display electrodes formed on a front substrate each of which is composed of a pair of a scanning electrode and maintenance electrode arranged in an opposite manner so as to form a discharge gap between them, the thickness of the front substrate is set to be not less than 1.5 mm and not more than 2.3 mm. Thereby, a noise level can be reduced when the display panel is operated between a low land and a high land of altitude 2,000 m or the like. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a plasma display panel.

[0002]

2. Description of the Related Art A plasma display panel is a display for displaying an image by exciting and emitting a phosphor with ultraviolet rays generated by gas discharge. The method of forming the discharge can be classified into an alternating current (AC) type and a direct current (DC) type.

The characteristic of the AC type is that it is superior to the DC type in terms of brightness, luminous efficiency and life. Further, of the AC type, the reflective surface discharge type is particularly outstanding in terms of brightness and luminous efficiency, and thus this type is the most common.

A conventional AC type plasma display panel (hereinafter referred to as PDP) will be described with reference to FIGS. 2 and 3.

FIG. 2 shows a panel structure of this PDP. As shown in FIG. 2, on a transparent front substrate 1 such as a glass substrate, scanning electrodes 2 facing each other in parallel with a discharge gap. A plurality of stripe-shaped display electrodes 4 forming a pair with the sustain electrodes 3 are formed. The scan electrodes 2 and the sustain electrodes 3 are composed of transparent electrodes 2a and 3a made of ITO, SnO ₂ or the like, and a silver thick film or aluminum thin film or chromium / copper / electrically connected to the transparent electrodes 2a and 3a. The bus electrodes 2b and 3b are made of a laminated thin film of chromium (Cr / Cu / Cr). Further, a dielectric layer 5 made of low melting point glass is formed on the front substrate 1 so as to cover the plurality of pairs of electrodes, and a protective film 6 made of MgO is formed on the dielectric layer 5. The front panel 7 is thus constructed.

A dielectric layer 9 is formed on the rear substrate 8 facing the front substrate 1 in a direction orthogonal to the display electrodes 4 of the scan electrodes 2 and the sustain electrodes 3. A plurality of stripe-shaped data electrodes 10 are formed.
A plurality of stripe-shaped partition walls 11 are arranged in parallel with the data electrodes 10 on the dielectric layer 9 between the data electrodes 10, and the phosphor layer 12 is provided on the side surface between the partition walls 11 and on the surface of the dielectric layer 9. The back panel 13 is provided.

The front panel 7 and the back panel 13 are composed of a scan electrode 2, a sustain electrode 3 and a data electrode 1.
They are arranged so as to face each other with a minute discharge space so as to be orthogonal to 0, and the periphery is sealed, and the discharge space contains a mixed gas of neon (Ne) and xenon (Xe) as a discharge gas. Is about 66.5 kPa (500T
filled at a pressure of orr). Also, the discharge space is
By partitioning into a plurality of partitions by partition walls 11, a plurality of discharge cells at which the intersections of the display electrodes 4 and the data electrodes 10 are located are provided, and each of the discharge cells has phosphors of red, green and blue. Layers 12 are sequentially arranged one by one.

In this PDP, several tens of kH is placed between the electrodes.
An AC voltage of z to several hundreds of kHz is applied to generate a discharge in the discharge space, and the phosphor layer is excited by the ultraviolet rays from the excited Xe atoms to generate visible light to perform a display operation.

FIG. 3 shows an electrode array diagram of this panel. As shown in FIG. 3, the electrodes have an m × n matrix configuration, and m columns of data electrodes D1 to Dm are arrayed in the column direction. And the scan electrodes SCN1 to SCN of n rows in the row direction.
CNn and sustain electrodes SUS1 to SUSn are arranged.

In this PDP, one field period is composed of a plurality of subfields having an initializing period, a writing period, a sustaining period and an erasing period, and the number of sustaining pulses for determining the sustaining discharge in each subfield. And the gradation display is performed by the combination of the subfields.

Explaining one example of this driving operation, first, an initialization pulse is applied to the scan electrodes SCN1 to SCNn shown in FIG. 3 to initialize the wall charges in the discharge cells of the panel. Next, in the writing period, since the first line is displayed,
A scan pulse voltage is applied to the scan electrode SCN1 of the first row,
A write pulse voltage is applied to the data electrode groups D1 to Dm corresponding to the discharge cells to cause a write discharge (address discharge) between the data electrode groups D1 to Dm and the scan electrode SCN1 of the first row, and the dielectric layer surface. Wall charges are accumulated in the first row, and the write operation (address operation) of the first row is performed.

The above operation is sequentially performed, and when the writing operation of the Nth row is completed, a latent image for one screen is written.

Next, in the sustain period, the data electrode group D1
To Dm are grounded, and first, all sustain electrode groups SUS1 to SU
A sustain pulse voltage is applied to Sn, a sustain pulse voltage is subsequently applied to all scan electrode groups SCN1 to SCNn, and then this operation is alternately continued to apply a sustain pulse voltage, thereby writing in the write period. In the discharge cells that have been operated, the sustain discharge continues to emit light, and the screen is displayed. After that, in the erase period, discharge is generated by applying an erase pulse having a narrow width, and the wall charges are extinguished, so that the erase operation is performed.

In this way, image display is performed by a series of driving methods including the initialization period, the writing period, the sustaining period, and the erasing period.

[0015]

By the way, in such a PDP, when the display drive is performed in an area where the atmospheric pressure of the outside air is low, particularly in a high altitude area, the pressure difference between the inside and the outside of the panel becomes small. Therefore, a slight vibration is generated at the boundary portion where the two bonded substrates are in contact with each other.
Noise of 0 dB or more may occur.

The present invention solves such a problem, and provides a panel structure which does not deteriorate in quality even when used at high altitudes.

[0017]

In order to solve such problems, the present invention is characterized in that the thickness of the front substrate is 1.5 mm or more and 2.3 mm or less.
According to the present invention, the PDP having a noise level of 30 dB or less during operation even at a high altitude of 2000 m from flat ground
Can be provided.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION First, the present inventors examined the cause of noise generation in a PDP. 20H, which is the frequency band of sounds (audible sounds) that humans can feel
Focusing on a frequency of z to 20 KHz, the noise level was regulated to 30 dB or less within this frequency range, and the examination was conducted. In other words, based on the idea that sound in the frequency band that does not originally remain as noise for humans does not pose a problem from the beginning, we focused on the frequency band that is perceived as noise and aimed to reduce the noise level in the frequency band that is perceived as noise. It is a thing.

The noise level referred to here is the sound pressure (2) based on the square of the effective value of the sound pressure weighted by the A characteristic.
It is 10 times the common logarithm of the value divided by the square of (0 μPa), that is, the A characteristic frequency weighted sound pressure level (J
IS (Japanese Industrial Standard) Z8731). Moreover, as this measuring method, Japanese Industrial Standard (JIS) C1505-
1988 and International Electrotechnical Commission (IEC) standard IEC6
A device according to 0651-IEC60804 is applied.
For example, Rion Co., Ltd. integral precision sound level meter NL-1
4 1/1, 1/3 octave filter unit N
A sound level meter such as X-05 can be used.

As a method of measuring the noise level in the PDP, the microphone is arranged at a distance of 50 mm perpendicular to the surface of the substrate glass of the panel display surface (incident angle is 0).
Install it so that it happens every 2 hours). First, the noise level of background noise in the state where the panel is not lit is measured. It is desirable to select several measurement points on the panel display surface. In addition, the center frequency of the filter is 20Hz
The measurement is performed by changing the frequency up to 20 kHz. Then, the noise level is measured in the same manner as above at the measurement point in the state of the single-color fixed display (for example, white) on the front surface of the panel display surface. The value obtained by subtracting the noise level when the panel is not lit from the noise level when the panel is turned on is the noise level of the noise generated when the panel is actually driven.

As a result of the present inventors' investigation of the cause of noise generation in the PDP, the front panel vibrates when a drive voltage is applied to the display electrodes of the front panel without connecting the back panel to the front panel. , No noise was observed. It was also found that the noise source was the highest at the joint between the front panel and the back panel. The audible sound is set to 20 Hz to 20 kHz, but it was found that the sound pressure level of noise of 2 kHz to 8 kHz is high.

From this, it is considered that the cause of the noise generation in the PDP is the collision between the front panel and the back panel in the part where there is a gap due to the vibration of the front panel to which the driving voltage is applied.

The present invention has been found based on such a viewpoint, that is, the invention according to claim 1 of the present invention forms a discharge space between a pair of substrates and arranges them so as to face each other. A PD formed by forming a plurality of display electrodes, which are a pair of electrodes facing each other with a discharge gap, on a front substrate.
P is characterized in that the thickness of the substrate on the front side is 1.5 mm or more and 2.3 mm or less. By reducing the thickness of the substrate, the resonance frequency is shifted to the high frequency side,
The noise level can be reduced.

Further, the present invention is characterized in that the front side substrate has a density of 2.2 g / cm ³ or more and 2.5 g / cm ³ or less.

Hereinafter, a PDP according to an embodiment of the present invention
Will be described.

First, the specific structure of the PDP according to the present invention.
First, the front panel will be explained.
On the glass substrate is a transparent material such as ITO or tin oxide.
Forming a transparent electrode made of bright conductive material, and
Thick silver (Ag) film, aluminum (Al) thin film or C
Bus electrodes such as r / Cu / Cr laminated thin films are sequentially laminated,
Furthermore, lead oxide (PbO) or bismuth oxide (Bi)
₂O₃) Or phosphorus oxide (PO _Four).
Lath dielectric layer formed by screen printing
And then protects the dielectric layer from plasma damage
A protective film made of gO is formed by electron beam evaporation or sputtering.
It is formed by forming by the ring method.

On the other hand, on the back panel side, a data electrode made of a silver (Ag) thick film, an aluminum (Al) thin film or a Cr / Cu / Cr laminated thin film is formed on a glass substrate, and the data electrode is covered. While forming a base dielectric layer made of a low melting point glass similar to the above, the partition wall containing glass as a main component is formed at a predetermined pitch, and a red phosphor in each space sandwiched by the partition walls, a green phosphor,
It is configured by forming a phosphor layer of a blue phosphor.

Next, the front panel and the back panel thus produced are attached to each other by using sealing glass, and a high vacuum (1
After exhausting to a pressure of 6 × 10 ⁻⁴ Pa), the discharge gas having a predetermined composition is set to a predetermined pressure, for example, a mixed gas of neon gas and xenon gas is set to 95% and 5% by volume, respectively, and the pressure is set to 6
Complete by encapsulating at 6.5 kPa (500 Torr).

FIG. 1 shows the frequency when a PDP having a glass substrate thickness of 2.8 mm (conventional panel), a glass substrate thickness of 2.3 mm and a glass substrate thickness of 2.5 mm is operated at a high altitude of 2000 m. It is a figure which compares and shows the result of having analyzed.

As shown in FIG. 1, in the conventional panel, 3
Sound pressure level of noise of 40 kHz from 6 kHz to 6 kHz
It can be seen that the point where the sound pressure level is high is shifted to the high frequency side of 6 kHz or more by thinning the glass substrate to 2.3 mm although it is high in the vicinity. In the high frequency region of 6 kHz or higher, the weighting of the A characteristic frequency becomes smaller, so that the noise level becomes low even if the sound pressure level is the same as in the low frequency region.

Further, when the noise level of the conventional panel and the thin panel of the glass substrate having a thickness of 2.3 m are compared on the level ground and the high level of 2000 m, the conventional panel is 20 dB on the level ground and 35 dB on the high level. On the other hand, a thin panel made of glass substrate has a level of 18 dB on flat ground and 28 dB on high ground.
And was below 30 dB.

This is because the resonance frequency can be shifted to the high frequency side by reducing the thickness of the substrate, and the noise level can be reduced.

When the substrate thickness is 1.5 mm or less,
Since the glass strength is weak, it may cause panel cracking.
If it is thicker than 10 mm, it exceeds 30 dB, so it is desirable to change it between 1.5 mm and 2.3 mm.

Here, the results of studying the difference in the density of the glass substrate will be explained. The glass substrate density is 2.8 g /
Using a soda-lime glass substrate of cm ³ and 2.5 g / cm ³ , frequency analysis and a noise level at a high altitude of 2000 m were measured in the same manner as in the above embodiment, and the density of the substrate was 2.5 g / cm 2. ^By lowering it to ³ , the resonance frequency shifts to the high frequency side, and the noise level is 20 dB on level ground,
It was 29 dB and 30 dB or less at high altitude. this is,
This is probably because the resonance frequency was shifted to the high frequency side and the noise level was reduced.

According to the results of the study conducted by the present inventors, when the density of the substrate is 2.2 g / cm ³ or less, the glass strength is weak, which causes panel cracking.
If it is higher than m ³ , it exceeds 30 dB, so 2.2 g / cm ³
It is desirable to change between 2.5 g / cm ^{3 and} less.

As described above, according to the present invention, the pair of substrates are arranged so as to face each other with a discharge space formed therebetween, and the front substrate is provided with a display electrode composed of a pair of electrodes facing each other with a discharge gap. In a plurality of plasma display panels formed, the thickness of the substrate on the front side is 1.5 mm or more and 2.3 mm or less. By reducing the thickness of the substrate, the resonance frequency becomes higher on the high frequency side. The noise level can be reduced by shifting to.

[0037]

As described above, according to the present invention, by setting the thickness of the substrate on the front side to be 1.5 mm or more and 2.3 mm or less, the noise level during operation in the highland such as an altitude of 2000 m from the level ground can be improved. The effect that it can be reduced is obtained.

[Brief description of drawings]

FIG. 1 is a characteristic diagram showing a comparison of results of frequency analysis performed on a plasma display panel according to an embodiment of the present invention and a conventional panel.

FIG. 2 is a perspective view showing a schematic structure of an AC type plasma display panel.

FIG. 3 is a wiring diagram showing an electrode array of the panel.

[Explanation of symbols]

1 substrate 2 scanning electrodes 3 sustain electrodes 4 display electrodes

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yusuke Takada             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 5C040 FA01 FA04 GA02 GB02 MA30

Claims (2)

[Claims] 1. A plasma display panel comprising a pair of substrates arranged opposite to each other with a discharge space formed therebetween, and a plurality of display electrodes formed of a pair of electrodes facing each other with a discharge gap formed on the front substrate. 2. The plasma display panel according to claim 1, wherein the thickness of the front substrate is 1.5 mm or more and 2.3 mm or less. 2. The density of the front substrate is 2.2 g / cm ³
The plasma display panel according to claim 1, wherein the plasma display panel is set to 2.5 g / cm ³ or less.