JP2002075206A - Manufacturing method and device of image display device and image display device manufactured using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma display panel used for display device and its manufacturing method in which the electric power at the aging process is reduced and a panel having stable discharge characteristics can be manufactured. SOLUTION: In the manufacturing process, impressing voltage value at the aging process is reduced after a certain time or at a certain cycle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image display device for displaying an image by plasma discharge between discharge electrodes, for example, a plasma display panel and a manufacturing process thereof.
In particular, the present invention relates to an aging process, and provides a method for manufacturing a panel with reduced discharge characteristics and stable discharge characteristics.

[0002]

2. Description of the Related Art The present invention is generally used for an image display apparatus for displaying an image by plasma discharge between discharge electrodes. Hereinafter, a plasma display panel will be described as an example.

A conventional plasma display panel generally has a configuration as shown in FIG.

[0004] The plasma display panel includes a front panel 100 and a rear panel 200. The front panel 100 includes a scan electrode 102 on a front glass substrate 101.
a, sustain electrodes 102b are alternately formed in a stripe shape, and are further formed by being covered with a dielectric glass layer 103 and a protective layer 104 made of magnesium oxide (MgO).

[0005] The back panel 200 comprises a back glass substrate 20.
1, an address electrode 202 is formed in a stripe shape, an electrode protection layer 203 is formed so as to cover the address electrode 202, and a partition wall 204 is formed in a stripe shape on the electrode protection layer 203 so as to sandwich the address electrode 202. Furthermore, the partition wall 20
It is formed by providing a phosphor layer 205 between the four. The front panel 100 and the rear panel 200 are bonded together, and a discharge space is formed by filling a discharge gas into a space 210 partitioned by the partition wall 204. The phosphor layer is usually red for color display.
Phosphor layers of three colors of green and blue are arranged in order.

In the discharge space 210, for example, a discharge gas obtained by mixing neon and xenon is usually 0.6 g.
It is sealed at a pressure of about 7 × 10 ⁵ Pa.

[0007] As described above, in the conventional production of a PDP, after each of a front substrate and a rear substrate is produced, as an assembly process,
The panel is bonded and sealed, exhausted, filled with gas, and sealed to form a panel. However, immediately after this assembly,
Panel lighting requires very high voltages. It is considered that this is because the impurity gas is adsorbed on the protective film / phosphor surface. Therefore, after the assembly process, aging is performed to discharge the entire discharge region for a certain period of time in order to remove the adsorbed impurity gas and stabilize the discharge characteristics of the panel.

The aging process is performed on the PDP fabricated as described above, as shown in FIG.
The scan electrode driving unit 230 and the sustain electrode driving unit 240 are connected, and all the address electrodes 202 are set to the same potential.
02a, the voltage is alternately applied to the sustain electrode 102b at a predetermined cycle. In the conventional aging process, the driving waveform applied at this time is such that the voltage value is always uniform during the processing period as shown in FIG.

[0009]

In this conventional aging process, a long discharge time of about 30 hours is required for stabilization of a desired discharge voltage, and the entire surface of the panel is displayed. Therefore, a high voltage and a high current value were required. For this reason, the power during the aging process becomes enormous, and there has been a problem of an increase in running cost at the time of manufacturing the PDP. In addition, for long-time processing,
There were various problems related to the environment at the time of manufacturing, such as the site area of the factory and the air conditioning equipment due to the heat generated by the panels. Further, it is clear that these problems will become even more serious as PDPs become larger in screen and mass-produced.

The present invention has been made in view of the above problems, and has as its object to provide a method for reducing power and heat generation during aging processing.

[0011]

First, the on / off state of the PDP during the aging process will be described.

At the time of lighting, when a voltage value on the scanning electrode side and the sustaining electrode side is gradually increased from 0 V, first, a certain cell in the panel surface is turned on (hereinafter, the voltage value at this time is set to one point). Lighting voltage Vf1). As the applied voltage is further increased, the number of lighting cells increases, and eventually the entire panel is lit (hereinafter, the voltage value at this time is referred to as a full lighting voltage Vfn).

On the other hand, at the time of turning off the light, if the applied voltage is gradually reduced from the state of full lighting, the lighting state of the entire panel becomes non-uniform, causing unevenness. Then, one point of a certain cell in the panel surface becomes invalid (hereinafter, the voltage value at this time is referred to as a one-point light-off voltage Ve1). As the applied voltage is further reduced, the number of unlit cells increases, and eventually the entire panel is turned off (hereinafter, the voltage value at this time is referred to as a full turn-off voltage Ven).

Here, the magnitude relationship between the above four types of voltage values will be described. Generally, for the voltage value required for discharge,
Since the voltage value at which the discharge ends is low, Vf1> Ve1 Vfn> Ven.

In the conventional aging method, the set voltage value is set at a value several tens V higher than Vfn. This is because the unevenness of the entire panel at the time of aging lighting and the aging efficiency are considered. However, because of this high set voltage value, a great deal of power consumption was required in the aging process in the past. Therefore, in the present invention, the power during the aging process is reduced by reducing the set voltage after a certain period of time or at a certain period. The voltage value Vs to be reduced was a voltage value satisfying Vf1>Vs> Ve1. As a result, the inventors succeeded in reducing the power value by about 30% (in the case of the invention of the first embodiment). Further, as an attendant effect of the present invention, a rise in panel temperature during the aging step is suppressed, so that the probability of panel cracking failure can be reduced. Further, the probability of dielectric breakdown failure can be reduced by lowering the applied voltage.

[0016]

(Embodiment 1) FIG. 1 shows a driving waveform at the time of aging according to Embodiment 1 of the present invention.

Conventionally, as shown in FIG. 4, the applied voltage value during aging has always been constant. In the present invention, a voltage value (Vt) exceeding the full lighting voltage Vfn is applied only at the time of lighting, and after a while, the voltage value is changed to a voltage value (Vs) exceeding the one-point lighting voltage Ve1. At this time, the circuit may be changed to a manual specification after a certain period of time by using a conventional specification.

The time for changing from voltage Vt to voltage Vs is
It is assumed that when the lighting is performed by the voltage Vt, the brightness is changed when there is no luminance unevenness in the panel surface. Also,
The set voltage Vs gradually decreases the applied voltage,
The lowest voltage that does not cause luminance unevenness in the panel surface. This is because there is a concern that the unevenness in the progress of the aging process will occur in the panel surface due to the uneven brightness in the panel surface.

However, there is a concern that the aging efficiency may be lowered due to the voltage drop. The inventors of the present invention investigate the time required for the discharge characteristics to stabilize with respect to the voltage value, and find that the applied voltage value has no effect on the aging efficiency. (Here, the aging efficiency is the time until the discharge voltage value stabilizes and the luminance change saturates, and the good aging efficiency indicates that this time is short.). Furthermore, in the panel according to the aging process of the present invention, a result was obtained in which erroneous discharge and the like were extremely reduced as compared with the panel according to the current aging process.

In the aging of the current PDP, 20
It is desirable that the high voltage period Tt be this time since luminance unevenness is substantially eliminated after about 30 minutes. In the low voltage period Ts, the number of discharges can be increased and the aging efficiency can be increased by shortening the width of the applied pulse, that is, by increasing the frequency of the applied voltage. This is because the applied voltage is reduced, and the power value is the same as that of the conventional aging method, the number of discharges is increased, the aging efficiency is increased, and the probability of dielectric breakdown failure is reduced due to the reduced applied voltage. Can be done.

(Embodiment 2) FIG. 2 shows a drive waveform at the time of aging in Embodiment 2 of the present invention. In the second embodiment, the voltage value Vt and the voltage value Vs are repeated at regular intervals. This is because, by returning the voltage value to the voltage value Vt at a certain fixed period, the luminance unevenness of the display is removed as compared with the first embodiment. When the fixed period time is T0, the time for keeping the voltage value Vt is Tt, and the time for keeping the voltage value Vs is Ts, T0 = Tt + Ts. The shorter Tt time is, It is effective, and most desirably one pulse as shown in FIG. According to the study by the inventors, T0 is 15
When it was 20 msec (ms), it was good. Further, the value of Vs at this time may be lower than the one-point light-off voltage Ve1. This is because the priming electrons are emitted into the cell discharge space by the discharge at the applied voltage Vt, the discharge starting voltage in the cell is reduced, and the aging discharge is completely generated even if the voltage is lower than Ve1. Although the period T0 is constant during the aging process here, there is no problem even if it changes irregularly.

(Embodiment 3) Embodiments of claims 5 to 7 will be described below. It was found that the setting voltage for the aging process was set to a minimum voltage value at which unevenness of panel luminance due to aging discharge did not occur, whereby the current aging effect was obtained and the power was suppressed. That is, it is effective to monitor the luminance of the panel during the aging process, determine the degree of the luminance unevenness from the measured value, and set the optimum voltage value each time. FIG. 6 shows an apparatus example of such a method. In this device, a measuring device for measuring luminance during the aging process and a control unit for determining a voltage value based on the luminance value are connected to a current aging device. As the measuring device, a case where a plurality of spot-type luminance measuring devices are arranged in a plane, a case where a CCD type imaging device having the same number or more of pixels as the display device to be aged, and the like are considered. Further, since the degree of luminance unevenness at the time of aging is reflected on the luminance unevenness of a normal image, it is desirable that the degree of this luminance distribution be suppressed to 10% or less. This is because the luminance distribution during aging is 10
This is because when the value is not less than%, the luminance distribution value is followed in the image display, and is a value that can be sufficiently identified by visual recognition.

[0023]

As described above, according to the present invention, the PD
In the step of performing an aging process for stabilizing the light emission characteristics of P, the applied voltage value is changed with time. In particular, the present invention is characterized in that the applied voltage is reduced, thereby providing a manufacturing method in which power during aging of a PDP manufacturing process is reduced.

Further, as an effect of the present invention, the rise in panel temperature during the aging step is suppressed, so that the probability of panel cracking failure can be reduced, and the probability of dielectric breakdown failure also decreases due to the decrease in applied voltage. Can be done. In addition, a panel with less erroneous discharge and showing stable discharge characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a time chart showing a driving waveform in an aging process according to a first embodiment of the present invention.

FIG. 2 is a time chart showing a driving waveform in an aging process according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing a connection state between a plasma display panel and a driving circuit during an aging process;

FIG. 4 is a time chart showing a driving waveform in a conventional aging process.

FIG. 5 is a partial perspective view showing a conventional plasma display panel.

FIG. 6 is a schematic view of an aging device according to a third embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 front panel 200 rear panel 101 front glass substrate 102 a scan electrode 102 b sustain electrode 103 dielectric glass layer 104 MgO protective layer 201 rear glass substrate 202 address electrode 203 electrode protective layer 204 partition wall 205 fluorescent layer 210 discharge space 220 address drive section 230 Scan electrode driver 240 Sustain electrode driver 301 Luminance measuring unit 302 Voltage controller 401 High voltage period 402 Low voltage period 403 One cycle period

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hideaki Yasui 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 5C012 AA09 VV01 VV02 5C040 FA01 FA04 GB03 GB14 JA24

Claims (10)

[Claims] 1. An image display device for displaying an image by plasma discharge between discharge electrodes in an aging process, wherein a voltage value for the discharge in the aging process is changed with time. Aging method. 2. The method according to claim 1, wherein the voltage value to be applied is reduced after the step of performing the aging process is started.
5. The aging method for an image display device according to item 1. 3. The aging method for an image display device according to claim 1, wherein the voltage value to be applied is reduced 20 to 30 minutes after the start of the aging process. 4. The aging method for an image display device according to claim 1, wherein the voltage value to be applied is reduced at a certain period of time after the start of the aging process. 5. An aging apparatus incorporating the aging method according to claim 1. 6. An aging process for an image display device for displaying an image by plasma discharge between discharge electrodes, wherein the aging process is performed so that a luminance value during the aging discharge in the surface of the image display device is made uniform. A control method for changing a voltage value for discharging the battery. 7. An image display device for displaying an image by plasma discharge between discharge electrodes is subjected to an aging process, wherein the luminance distribution at the time of the aging discharge in the surface of the image display device is 10% or less. 7. The control method according to claim 6, wherein a voltage value for discharging in the aging process is changed. 8. An apparatus for performing an aging process on an image display device for displaying an image by plasma discharge between discharge electrodes, comprising: means for measuring a luminance value of an aging discharge in the surface of the image display device; An aging apparatus comprising means for changing a voltage value for discharging in an aging process. 9. An image display device manufactured by the aging method and the aging device according to claim 1. 10. The aging method for an image display device according to claim 1, wherein the image display device is a plasma display panel.