Plasma display panel and method for driving the same

An improved plasma display panel and a method for driving the same are disclosed. Illustratively, the plasma display panel includes a plurality of address electrodes and a plurality of scan electrodes and sustain electrodes, and displays video data through dual scanning. A temperature sensor included in the plasma display panel detects a temperature of the plasma display panel. When the detected temperature is determined to be low, a scanning direction in which a voltage is applied to the scan electrodes is controlled such that the plasma panel is scanned from both ends to the center. When the detected temperature is determined to be high, a scanning direction in which a voltage is applied to the scan electrodes is controlled such that the plasma panel is scanned from a top towards the center. Altering the scan direction based on temperature improves picture quality.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority of Korea Patent Application No. 2003-61187 filed on Sep. 2, 2003 in the Korean Intellectual Property Office, the content of which is herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a plasma display panel, and more particularly, to a plasma display panel (PDP) whose scanning direction can be controlled in response to a detected operating temperature. A method for driving the PDP in response to a detected operating temperature is also disclosed.

2. Description of the Related Art

A plasma display panel is a flat panel display that displays characters or images using plasma generated by gas discharge. The plasma display panel is constructed in a manner such that more than hundreds of thousands to millions of pixels are arranged in a matrix form depending on the size of the panel. PDPs are classified as a Direct Current (DC) or an Alternating Current (AC) type based on the waveform of a driving voltage applied thereto and the structure of the display's discharge cells.

In general, an AC type plasma display panel is driven using a reset interval, an addressing interval, and a sustain interval. The reset interval erases wall charges formed by a previous sustain discharge, and initializes a state of each cell to smoothly carry out a next addressing operation. The addressing interval discriminates addressed cells in the panel from non-addressed cells and accumulates wall charges in the addressed cells. The sustain interval carries out the discharge to display an image on each addressed cell. During the sustain interval, a sustain pulse is alternately applied to a scan electrode and a sustain electrode to create the sustain discharge to display an image on the panel.

When the plasma display panel is driven, a scanning direction of a scan electrode driver is set in one direction. This generates a discharge difference depending on whether the first scanning line is located in the center or edge of the plasma display panel, or creates a discharge difference between the first scanning line and the last scanning line. Accordingly, one of two disadvantages occurs. The discharge difference either reduces a margin of the plasma display panel or generates a luminance difference between upper and lower parts of the plasma display panel, both of which adversely affect image quality.

The luminance difference between the upper and lower parts of the panel may be reduced or eliminated by scanning the PDP from the center outwards to the ends thereof. However, the discharge characteristics of a center-scanned PDP vary at a low or high operating temperature and generate an unstable discharging operation of the first scanning line. Accordingly, poor discharge occurs in scanning lines located in the center of the panel, which adversely affects image clarity and quality. A solution is needed that improves a PDP's discharge characteristics at low and high operating temperatures.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a plasma display panel and a method for driving the same in which the plasma display panel, in response to a detected low or high operating temperature, is scanned starting from the end thereof to reduce the influence of that poor discharge of the first scanning line has on images.

In one aspect of the present invention, a plasma display panel that receives external video data and displays gray scales through dual scanning includes a plasma panel having a plurality of address electrodes, a plurality of scan electrodes, and a plurality of sustain electrodes. The PDP further includes a temperature sensor for sensing a temperature of the plasma panel, and a controller that receives video data to generate an address electrode driving signal, a sustain electrode driving signal, and a scan electrode driving signal. In response to a detected low or high temperature, the controller may alter a scanning direction such that the PDP is scanned from an end thereof to the center of the panel. For example, the controller may also rearrange the address electrode driving signal that corresponds to the controlled scanning direction when the temperature sensed by the temperature sensor is lower than a first temperature. The PDP may further include an address electrode driver that applies a voltage corresponding to the address electrode driving signal to the address electrodes; a sustain electrode driver that applies a sustain voltage to the sustain electrodes in response to the sustain electrode driving signal of the controller; and a scan electrode driver that determines a scanning direction according to a control signal of the controller and applies a voltage to the scan electrodes in response to the scan electrode driving signal.

In another aspect of the present invention, a plasma display panel that receives external video data and displays gray scales includes a plasma panel having a plurality of address electrodes, a plurality of scan electrodes, and a plurality of sustain electrode. The PDP may further include a temperature sensor for sensing a temperature of the plasma panel, and a controller that receives the video data to generate an address electrode driving signal, a sustain electrode driving signal, and a scan electrode driving signal. The controller may change a scanning direction when the temperature sensed by the temperature sensor is higher than a first temperature or lower than a second temperature. The PDP may further include an address electrode driver that applies a voltage corresponding to the address electrode driving signal to the address electrodes; a sustain electrode driver that applies a sustain voltage to the sustain electrodes in response to the sustain electrode driving signal of the controller; and a scan electrode driver that determines a scanning direction according to a control signal of the controller and applies a voltage to the scan electrodes in response to the scan electrode driving signal.

Another aspect of the present invention discloses a method for driving a plasma display panel that includes a plurality of address electrodes and a plurality of scan electrodes and sustain electrodes and that displays video data through dual scanning. Illustratively, the method may include: sensing a temperature of the plasma display panel, and receiving external video data to generate an address electrode driving signal, a sustain electrode driving signal, and a scan electrode driving signal. The method may further include altering a first scanning direction in response to a detected temperature such that the plasma display panel is scanned from both ends to the center thereof. For example, the address electrode driving signal may be rearranged in response to the altered scanning direction when the sensed temperature is lower than a first temperature. The method may further include applying a rearranged address electrode driving signal to the address electrodes, applying a sustain voltage to the sustain electrodes in response to the sustain electrode driving signal, and applying, in response to a control signal, a voltage to the scan electrodes that varies according to the scan electrode driving signal.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1shows a configuration of a PDP according to an embodiment of the present invention. Referring toFIG. 1, the PDP according to the invention includes a plasma panel100, a controller200, an address electrode driver300, a sustain electrode driver (referred to as “X electrode driver” hereinafter)400, a scan electrode driver (referred to as “Y electrode driver” hereinafter)500, and a temperature sensor600.

The plasma panel100includes a plurality of address electrodes A1through Am arranged in the row direction, and a plurality of sustain electrodes (referred to as “X electrodes”hereinafter) Xlhrough Xnand scan electrodes (referred to as “Y electrodes” hereinafter) Ylthrough Ynarranged in the column direction. The X electrodes Xlhrough Xnrespectively correspond to the Y electrodes Ylhrough Yn, and in general, ends of the X electrodes Xlthrough Xnat one side are commonly connected. The plasma panel100further includes a glass substrate (not shown) on which the X electrodes Xlhrough Xnand the Y electrodes Ylhrough Ynare arranged, and a glass substrate (not shown) on which the address electrodes Alhrough Amare arranged. The two glass substrates face each other having a discharge space between them such that the X and Y electrodes Xlhrough Xnand Ylhrough Ynintersect the address electrodes Althrough Am. As shown, discharge cells are formed at the intersections of the address electrodes Alhrough Amand the X and Y electrodes Xlhrough Xnand Ylhrough Yn.

The temperature sensor600primarily senses a temperature of the plasma panel100, but may be configured to sense an external temperature, if required.

The controller200receives an external video signal and outputs an address electrode driving signal, an X electrode driving signal, and a Y electrode driving signal. In addition, the controller200determines a temperature sensed by the temperature sensor600. When the sensed temperature is low or high, the controller200controls a Y electrode driving signal scanning direction to be changed and rearranges address data to output an address electrode driving signal corresponding to the rearranged address data. Furthermore, the controller200divides one frame into a plurality of sub-fields and drives the sub-fields if required. Each of the sub-fields includes a reset interval, an addressing interval, and a sustain interval.

The address electrode driver300receives the address electrode driving signal from the controller200and applies a display data signal for selecting discharge cells to be displayed to the address electrodes Althrough Am. The X electrode driver400receives the X electrode driving signal from the controller200and applies a driving voltage to the X electrodes Xlhrough Xn. The Y electrode driver500receives the Y electrode driving signal from the controller200and supplies a driving voltage to the Y electrodes Ylhrough Yn.

As shown inFIG. 1, the controller200includes a gamma corrector210, an address data generator220, a data rearranging unit230, an automatic power controller240, and a scanning direction determining unit250.

The gamma corrector210receives a video signal and corrects a gamma value of the video signal on the basis of characteristics of the plasma display panel. The automatic power controller240measures an average signal level of video data output from the gamma corrector210and controls the power of the X electrode driving signal and Y electrode driving signal in response to the measured average signal level. The automatic power controller240divides the power-controlled data into N sub-fields if required and outputs the X electrode driving signal and Y electrode driving signal for each of the sub-fields.

The address data generator220generates address data from the video signal and outputs it as the address electrode driving signal. The scanning direction determining unit250controls a scanning direction of the Y electrode driving signal to be changed and outputs a control signal to the data rearranging unit230to rearrange the address data when the scanning direction determining unit250determines that a temperature sensed by the temperature sensor600is low. The data rearranging unit230rearranges the address data in response to the control signal output from the scanning direction determining unit250and outputs a Y electrode driving signal corresponding to the rearranged address data.

The operation of the plasma display panel having the above-described configuration according to one embodiment of the present invention will now be explained. A dual scanning technique that scans the plasma panel100from the top to the bottom of the plasma panel100at the normal temperature will be described in the following embodiment of the invention. Because the details of dual scanning are known in the art, a detailed explanation therefor is omitted. Given the following disclosure, such conventional dual scanning techniques may be adapted by a person of ordinary skill in the art to produce various embodiments of the invention.

Referring again toFIG. 1, the gamma corrector210of controller200receives an external video signal and corrects a gamma value of the video signal based on the individual characteristics of the PDP. Consequently, the gamma values will differ for each particular PDP.

The automatic power controller240measures an average signal level of the video data output from the gamma corrector210, controls power in response to the measured average signal level to generate sustain pulse information, and respectively outputs, to the X electrode driver400and the scanning direction determining unit250, an X electrode driving signal and a Y electrode driving signal that correspond to the sustain pulse information. In one embodiment, the automatic power controller240divides one frame into N sub-fields and generates the sustain pulse information for each of the sub-fields to provide the X electrode driving signal and Y electrode driving signal, if required.

The address data generator220generates address data from the video data output from the gamma corrector210and outputs it to the data rearranging unit230.

The temperature sensor600senses an operating temperature of the plasma panel100(or an exterior operating temperature) and outputs the detected temperature to the scanning direction determining unit250.

The scanning direction determining unit250determines whether the temperature sensed by the temperature sensor is high or low. Prior to operation of the PDP described above, a temperature at which poor discharging occurs is obtained experimentally, and is set to a first reference temperature as a basis of determining a low temperature. A different higher temperature may be experimentally determined and set to a second reference temperature as a basis of determining a high temperature. For example, temperatures lower than ten degrees centigrade may be determined to be low temperatures, and temperatures higher than fifty degrees centigrade may be determined to be high temperatures. Thus, various experiments may be made for one or more PDP's, of the same of similar types, to determine the PDP-specific low and high temperatures at which poor discharging occurs. The term “PDP-specific” means that the low and high temperatures at which poor discharging occurs may vary for each particular PDP tested. Consequently, the invention is not limited to the particular illustrative ranges of low and high temperatures listed above.

In one embodiment, when the sensed temperature is lower than a first reference temperature, the scanning direction determining unit250outputs the Y electrode driving signal such that the plasma panel is scanned from both ends to the center thereof. In addition, the scanning direction determining unit250outputs a control signal to the data rearranging unit230to rearrange the address data in response to the determined scanning direction.

In another embodiment, if the sensed temperature is higher than the second reference temperature (or a different reference temperature), the scanning direction determining unit250may determine that the sensed temperature lies above a range of normal operating temperatures, and output the Y electrode driving signal such that the plasma panel100is scanned from the top to is the bottom thereof. In addition, the scanning direction determining unit250outputs a control signal to the data rearranging unit230to output the address data as it is. For sensed temperatures that exceed a range of normal operating temperatures, either the top-to-bottom or end-to-center dual scanning techniques may be used in order to improve picture quality.

Illustratively, the data rearranging unit230may be configured to rearrange the address data only when a low temperature, indicated by the control signal of the scanning direction determining unit250is detected. Thus, in response to a detected low temperature, the data rearranging unit230outputs address electrode driving signal corresponding to the rearranged address data to the address electrode driver300.

In response to the address electrode driving signal, the address electrode driver300applies a display data signal for selecting discharge cells to be displayed to the address electrodes Althrough Am.

The X electrode driver400receives the X electrode driving signal and applies a driving voltage to the X electrodes Xlhrough Xn, and the Y electrode driver500supplies a driving voltage to the Y electrodes Ylhrough Ynaccording to the Y electrode driving signal.

A scanning direction based on a temperature is explained in more detail with reference toFIG. 2. Before continuing, however, it should be noted that, in general, the following phenomena may occur in the plasma display panel.

(1) If the temperature of the upper part of the plasma panel100is higher than its lower part when operating the plasma panel100a temperature difference between the upper and lower parts may become larger than ten degrees centigrade as the plasma panel100size increases. Consequently, when a large PDP operates at the normal temperature or at a temperature lower than the normal temperature, an increase in discharge delay results in poor address writing, which causes low discharge and poor image quality.

(2) The discharge delay increases when no priming particles are inside the plasma panel100.

(3) As a scanning operation is retarded, the discharge delay becomes longer due to a variation in states of wall charges and space charges in the cells of the plasma panel100.

(4) Unlike the case (3), the first scan line is the most vulnerable to discharge because it cannot receive a priming effect from a previous scanning operation.

In general, the plasma display panel is affected by the discharge delays of all the cases (1), (2), (3), and (4). Which phenomenon will affect a PDP during operation depends on a fabricating process used to manufacture the PDP or on one or more materials used to make the PDP. As shown inFIG. 2, the scanning direction is determined by taking into consideration the aforementioned four cases.

For example, when the plasma panel100(FIG. 1) is operated at the normal temperature for a predetermined period of time, the temperature of one part of the plasma panel100(illustratively the top part) increases, and a temperature difference may be generated between upper and lower parts of the plasma panel100. Thus, the discharge delay is generated due to phenomena (1) and (2) so that low discharge occurs in the plasma panel100. To provide a normal discharge, embodiments of the present invention provide a scanning direction from the upper part to the lower part of the plasma panel100.

At the lower part of the plasma panel100, a low temperature exists, and the phenomenon (4) becomes dominant. Thus, a first scan line (e.g., center line), becomes insufficiently discharged, and is unpleasant to the eye of a viewer. To reinstate a more pleasing picture, embodiments of the present invention scan the plasma panel100from bottom towards the top because the phenomenon (1) is not significant when the plasma panel100is operated at a low temperature. In this manner, dual scanning (top down for high temperature parts of the plasma panel100and bottom up for low temperature parts of the plasma panel100) may be used to improve overall picture quality.

Referring now toFIG. 2, a PDP having a normal temperature is shown. At the normal temperature, dual scanning is carried out from the top to the bottom of the plasma panel100because the Y electrode driver500outputs the Y electrode driving signal in a normal fashion.

However, in an embodiment of the invention, in response to a detected low temperature in the lower part of the plasma panel100, the Y electrode driver500outputs the Y electrode driving signal such that the scanning direction is changed, and dual scanning (top down for high temperature areas, and bottom up for low temperature areas) is executed from both ends to the center of the plasma panel100.

As one of ordinary skill in the art will appreciate, there are various methods of changing the scanning direction according to the Y electrode driver500in response to the control signal of the scanning direction determining unit250. For example, the scanning direction determining unit250may rearrange the Y electrode driving signal, or output a control signal to the Y electrode driver500to re-designate positions of Y electrodes to which the Y electrode driving signal is applied.

Additionally, the data rearranging method of the data rearranging unit230may be modified in various ways. If required, the functions of the data rearranging unit230and scanning direction determining unit250may be included in the address data generator220and automatic power controller240.

In the aforementioned embodiment of the invention, even if poor discharge occurs in the first line at a low temperature, scanning is carried out from both ends of the plasma panel100so that picture quality is not largely deteriorated.

While dual scanning by the Y electrode driver500has been explained in the aforementioned embodiment, the present invention may also be applied to other scanning methods.

For example, a second embodiment of the present invention in which scanning direction is varied at the normal temperature and a high temperature will now be explained.

The configuration of the plasma display panel in the second embodiment of the invention is identical to that of the plasma display panel in the first embodiment, and only the functions of the scanning direction determining unit250and data rearranging unit230in the second embodiment are slightly different from those in the first embodiment.

In the second embodiment, the scanning direction determining unit250controls the scanning direction of the Y electrode driving signal to be changed and outputs a control signal to the data rearranging unit230to rearrange the address data when it determines that a temperature sensed by the temperature sensor600is low or high. The data rearranging unit230rearranges the address data in response to the control signal of the scanning direction determining unit250and outputs a Y electrode driving signal corresponding to the rearranged address data.

FIG. 3shows a scanning direction of the plasma display panel based on a temperature according to the second embodiment of the present invention. Referring toFIG. 3, when the plasma display panel operates at the normal temperature for a predetermined period of time, the temperature of the plasma panel100increases to generate a temperature difference between upper and lower parts of the plasma panel100. However, low discharge does not occur at the normal temperature even when there is a temperature difference. In this case, a luminance difference between the upper and lower parts of the plasma panel100, caused by scanning from the center of the plasma panel100, can be reduced by using dual scanning that starts from each end of the plasma panel100and moves towards the center.

At a low temperature, similar to the first embodiment, the phenomenon (4) becomes larger so that a center line, that is, the first scan line, becomes insufficiently discharged. Accordingly, the plasma panel100is scanned from both ends to the center thereof when the plasma panel100is operated at a low temperature. This can minimize the influence of low discharge of the first scan line on images.

At a high temperature, low discharge may occur in the plasma panel100when the discharge delay according to the phenomena (1) and (3) occurs. Accordingly, when high temperature is detected, embodiments of the invention alter the normal scan mode to scan from the top to the bottom of the plasma panel100. On the other hand, when a normal operating temperature is detected, the Y electrode driver500outputs the Y electrode driving signal such that dual scanning is carried out from the center to both ends of the plasma panel100.

Referring toFIG. 3, a low temperature is detected, and the Y electrode driver500outputs the Y electrode driving signal in a scanning direction opposite to the scanning direction at the normal temperature such that dual scanning is carried out from both ends to the center of the plasma panel100. As mentioned previously, there are various methods of changing the scanning direction by the Y electrode driver500in response to the control signal of the scanning direction determining unit250.

At a high temperature, the Y electrode driver500outputs the Y electrode driving signal in the same scanning direction as the scanning direction as the normal temperature in the first embodiment such that dual scanning is carried out from the top to the bottom of the plasma panel100.

In one embodiment, the plasma display panel may be configured such that the controller carries out dual scanning on the plasma panel100from a center of the plasma panel100to each end thereof when the temperature sensed by the temperature sensor is higher than a first reference temperature and lower than a second temperature.

As described above, the present invention may change the scanning direction at a high or low temperature to prevent picture quality from being deteriorated due to poor sustain discharge. Furthermore, the present invention may remove a luminance difference between upper and lower parts of a plasma panel without reducing a margin of the plasma panel.