KR20080027060A - Plasma display panel device - Google Patents

Abstract

A plasma display apparatus is provided to improve image quality by embodying the third gray scale having the intensity of intermediate light between first and second gray scales. A unit frame is divided into plural subfields(1SF-14SF) having different numbers of illuminations so as to embody the gray scale of image. The subfields include reset, address, and sustain periods. Sustain signals are not applied to subfields for not generating discharge among the plural subfields. A third gray scale between first and second gray scales is embodied by applying the sustain signals having discharge numbers to at least one of the plural subfields. The discharge numbers are between the discharge numbers for embodying the first and second gray scales.

Description

Plasma display panel device

1 is a perspective view showing a first embodiment of a plasma display panel according to the present invention.

FIG. 2 is a timing diagram illustrating a first embodiment of a method of time-division driving by dividing one frame into a plurality of subfields.

FIG. 3 is a table illustrating a first embodiment of a mapping state of subfields according to gray scales of a plasma display panel.

<Explanation of symbols on main parts of the drawings>

10: front panel 11: scan electrode

12: sustain electrode 11a, 12a: transparent electrode

11b and 12b: metal bus electrodes 11c and 12c: second black matrix

13: upper dielectric layer 14: protective film

15: first black matrix 20: back panel

21: bulkhead 21a: vertical bulkhead

21b: transverse bulkhead 22: address electrode

23 phosphor layer 24 lower dielectric layer

The present invention relates to a plasma display device, and more particularly, to a plasma display device for implementing a third grayscale having an intermediate amount of light between a first grayscale and a second grayscale implemented based on a subfield mapping among grayscales of an image. will be.

Plasma display devices are not only easy to enlarge and thin, but also have a simple structure, which makes them easy to manufacture and has a higher luminance and higher luminous efficiency than other flat panel displays.

Conventional plasma display apparatuses implement gradation of an image based on subfield mapping, and the amount of light according to the gradation of the image is different.

However, in the plasma display apparatus of the related art, in implementing the grayscale of an image based on subfield mapping, there is a problem in that a difference in the amount of light between the adjacent first grayscale and the second grayscale among the plurality of grayscales is increased.

An object of the present invention relates to a plasma display apparatus for implementing a third grayscale having an intermediate amount of light between a first grayscale and a second grayscale implemented based on subfield mapping among grayscales of an image.

In the plasma display apparatus of the present invention, a unit frame is divided into a plurality of subfields having different emission counts in order to realize gray levels of the image, and each of the plurality of subfields includes a reset period, an address period, and a number of discharges of the sustain signal. The sustain signal is divided into a sustain period for implementing gray levels, and the sustain signal is not applied to the subfields that do not cause discharge among the plurality of subfields, and the third gray level between the first gray level and the second gray level is the first gray level. Is implemented by applying the sustain signal having a predetermined number of discharges to at least one of the plurality of subfields.

Hereinafter, a plasma display device according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view showing a first embodiment of a plasma display panel according to the present invention.

Referring to FIG. 1, the plasma display panel includes scan electrodes 11, sustain electrodes 12, sustain electrodes 12, and address electrodes 22 formed on the back panel 20, which are pairs of sustain electrodes formed on the front panel 10. do.

The sustain electrode pairs 11 and 12 generally include transparent electrodes 11a and 12a and bus electrodes 11b and 12b formed of indium tin oxide (ITO), and bus electrodes 11b and 12b. Silver may be formed of a metal such as silver (Ag), chromium (Cr), or a lamination of chromium / copper / chromium (Cr / Cu / Cr) or a lamination of chromium / aluminum / chromium (Cr / Al / Cr). The bus electrodes 11b and 12b are formed on the transparent electrodes 11a and 12a to serve to reduce voltage drop caused by the transparent electrodes 11a and 12a having high resistance.

Meanwhile, according to the first embodiment of the present invention, the sustain electrode pairs 11 and 12 have a structure in which the transparent electrodes 11a 12a and the bus electrodes 11b and 12b are stacked, and the bus electrodes 11b and 12b are enumerated above. In addition to one material, various materials such as photosensitive silver may be possible.

Light between the transparent electrodes 11a and 12a of the scan electrode 11 and the sustain electrode 12 and the bus electrodes 11b and 11c to absorb external light generated outside the front panel 10 to reduce reflection. Black matrixes (BMs, 15) are arranged that function as blocking and improve the purity and contrast of the front panel 10.

The black matrix 15 according to the first embodiment of the present invention is formed on the front panel 10. The first black matrix 15 and the transparent electrodes 11a, which are formed at positions overlapping the partition wall 21 are formed. The second black matrices 11c and 12c formed between 12a and the bus electrodes 11b and 12b may be formed. Here, the first black matrix 15 and the second black matrices 11c and 12c, also referred to as black layers or black electrode layers, may be simultaneously formed and physically connected in the formation process, or may not be simultaneously connected to each other. The first black matrix 15 may not be formed, and only the second black matrices 11c and 12c may be formed.

In addition, when physically connected and formed, the first black matrix 15 and the second black matrix 11c and 12c may be formed of the same material, but may be formed of different materials when they are formed separately.

Here, the bus electrodes 11b and 12b are stacked with the stacked second black matrices 11c and 12c and the transparent electrodes 11a and 12a. In other words, the bus electrodes 11b and 12b are stacked at predetermined distances from one edges of the second black matrices 11c and 12c and stacked with the transparent electrodes 11a and 12a by the predetermined distance.

Accordingly, the bus electrodes 11b and 12b are integrally formed because the bus electrodes 11b and 12b are spaced apart by the predetermined distance from one edges of the second black matrices 11c and 12c. However, the bus electrodes 11b and 12b may be formed in a separate type rather than in an integral form.

An upper dielectric layer 13 and a passivation layer 14 are stacked on the front panel 10 having the scan electrode 11 and the sustain electrode 12 side by side. Charged particles generated by the discharge are accumulated in the upper dielectric layer 13, and the protective electrode pairs 11 and 12 may be protected. The protective film 14 protects the upper dielectric layer 13 from sputtering of charged particles generated during gas discharge, and increases emission efficiency of secondary electrons. In addition, magnesium oxide (MgO) may be generally used for the protective film 14, and Si-MgO to which silicon (Si) is added may be used. Here, the content of silicon (Si) added to the protective film 14 may be 50PPM to 200PPM based on the weight percent (wt%).

On the other hand, the address electrode 22 is formed in the direction crossing the scan electrode 11 and the sustain electrode 12. In addition, the lower dielectric layer 24 and the partition wall 21 are formed on the back panel 20 on which the address electrode 22 is formed.

In addition, the phosphor layer 23 is formed on the surfaces of the lower dielectric layer 24 and the partition wall 21. The partition wall 21 has a vertical partition wall 21a and a horizontal partition wall 21b formed in a closed shape, and physically distinguishes discharge cells, and prevents ultraviolet rays and visible light generated by the discharge from leaking into adjacent discharge cells.

In the first embodiment of the present invention, not only the structure of the partition wall 21 illustrated in FIG. 1, but also the structure of the partition wall 21 having various shapes may be possible. For example, a channel in which a channel usable as an exhaust passage is formed in at least one of the differential partition structure, the vertical partition 21a, or the horizontal partition 21b having different heights of the vertical partition 21a and the horizontal partition 21b. A grooved partition structure having a groove formed in at least one of the type partition wall structure, the vertical partition wall 21a, or the horizontal partition wall 21b may be possible.

Here, in the case of the differential partition wall structure, the height of the horizontal partition wall 21b is more preferable, and in the case of the channel partition wall structure or the groove partition wall structure, it is preferable that a channel is formed or the groove is formed in the horizontal partition wall 21b. something to do.

On the other hand, in the first embodiment of the present invention is shown and described that each of the R, G and B discharge cells are arranged on the same line, it may be arranged in a different shape. For example, a Delta type arrangement in which R, G, and B discharge cells are arranged in a triangular shape may be possible. In addition, the shape of the discharge cell may be not only rectangular, but also various polygonal shapes such as a pentagon and a hexagon.

In addition, the phosphor layer 23 emits light by ultraviolet rays generated during gas discharge to generate visible light of any one of red (R), green (G), and blue (B). Here, an inert mixed gas such as He + Xe, Ne + Xe and He + Ne + Xe for discharging is injected into the discharge space provided between the upper / lower substrates 10 and 20 and the partition wall 21.

FIG. 2 is a timing diagram illustrating a first embodiment of a method of time-division driving by dividing one frame into a plurality of subfields.

Referring to FIG. 2, a unit frame may be divided into a predetermined number, for example, eight subfields SF1,..., SF8 to realize time division gray scale display. Each subfield SF1, ... SF8 is divided into a reset section (not shown), an address section A1, ..., A8, and a sustain section S1, ..., S8. .

Here, according to the first embodiment of the present invention, the reset period may be omitted in at least one of the plurality of subfields. For example, the reset period may exist only in the first subfield or may exist only in a subfield about halfway between the first subfield and all the subfields.

In each address section A1, ..., A8, a display data signal is applied to the address electrode X, and scan pulses corresponding to each scan electrode Y are sequentially applied.

In each of the sustain periods S1, ..., S8, a sustain signal is alternately applied to the scan electrode Y and the sustain electrode Z, so that wall charges are formed in the address periods A1, ..., A8. Sustain discharge occurs in the discharge cells.

The luminance of the plasma display panel is proportional to the number of discharges of the sustain signal applied in the sustain discharge periods S1, ..., S8 occupied in the unit frame. When one frame forming one image is represented by eight subfields and 256 gray levels, each subfield in turn has a different sustain at a ratio of 1, 2, 4, 8, 16, 32, 64, and 128. The number of pulses can be assigned. In order to obtain luminance of 133 gray levels, sustain discharge may be performed by addressing discharge cells during the first subfield period, the third subfield, and the eighth subfield.

The number of sustain discharges allocated to each subfield may be variably determined according to weights of the subfields according to the APC (Automatic Power Control) step. That is, the case in which one frame is divided into eight subfields has been described as an example. However, the present invention is not limited thereto, and the number of subfields forming one frame may be variously modified according to design specifications. For example, the plasma display panel may be driven by dividing one frame into eighth or more subfields, such as a twelfth or fourteenth subfield.

The number of sustain discharges allocated to each subfield can be variously modified in consideration of gamma characteristics and panel characteristics. For example, the gray level assigned to the fourth subfield may be lowered from 8 to 6 and the gray level assigned to the sixth subfield may be increased from 32 to 34.

FIG. 3 is a table illustrating a first embodiment of a mapping state of a subfield according to a gray level of a plasma display panel.

3 is taken as an example. Referring to FIG. 3, mapping of subfields is shown based on gray levels.

That is, FIG. 3 shows the subfields causing discharge and the subfields without generating discharge among the plurality of subfields according to the gradation and the light amount.

Referring to FIG. 3, the plasma display apparatus of the present invention may implement gradation display based on the number of discharges of the sustain signal corresponding to each subfield, which has been described with reference to FIG. 2.

In addition, in the non-polar A portion of FIG. 3, a sustain signal having a discharge number is applied only to the second subfield 2SF among the plurality of subfields 1SF to 14SF in two gray levels, so that the discharge cell discharges. The sustain signal is not applied to the remaining subfields.

In addition, a sustain signal having a discharge number is applied to only the first subfield 1SF and the third subfield 3SF among the plurality of subfields 1SF to 14SF in the four gray levels, so that the discharge cells are discharged and the remaining subfields are discharged. No sustain signal is applied to the field.

The light amount of the two gray levels is about 5.02, and the light amount of the four gray levels is about 10.97. At this time, the difference in the amount of light between the two and four gray levels is about 5, and the difference in the amount of light in the other neighboring gray levels is about 2 to 3.

Accordingly, three grayscales having an intermediate light amount between the two grayscales and the four grayscales are implemented. That is, the three gradations are the gradations of the light amount between the two gradations and the four gradations, and are not implemented in the set subfield mapping.

The implementation method of the three gray scales is implemented by applying a sustain signal having the number of discharges to indicate the difference amount of light between the two and four gray scales to a plurality of subfields in which the sustain signal is not applied in the two gray scales and thus does not discharge. do.

That is, for example, in the plasma display device, a sustain signal having 100 discharge numbers is applied to the second subfield 2SF to implement the two gray levels, and the first and third subfields to implement the four gray levels. Assume that a sustain signal having 200 discharge numbers at (1SF, 3SF) is applied.

In this case, since the two grayscales have a light quantity of about 5.02 and the four grayscales have a light quantity of about 10.97, one of the subfields that does not cause discharge during the implementation of the two grayscales so that the three grayscales have a light quantity of about 7.5. Use

That is, the three gray scales are implemented by adding only the middle of the number of discharges of the two and four gray scales to the sustain signal having the number of 100 discharges for implementing the two gray scales.

Accordingly, in the implementation of the three gray scales, a light amount of about 7.5 may be generated by applying a sustain signal having 50 discharge numbers to at least one of the plurality of subfields 3SF to 14SF.

Here, the three gray levels are not set in the subfield mapping, and may be added only to grayscales which are not set between neighboring tones or on the subfield mapping.

Although a preferred embodiment of the present invention has been described in detail above, those skilled in the art to which the present invention pertains can make various changes without departing from the spirit and scope of the invention as defined in the appended claims. It will be appreciated that modifications or variations may be made. Accordingly, modifications to future embodiments of the present invention will not depart from the technology of the present invention.

The plasma display apparatus according to the present invention implements a third grayscale having an intermediate amount of light between the first grayscale and the second grayscale based on the subfield mapping among the grayscales of the image, thereby adjusting the grayscale not set on the subfield mapping. By making it possible to implement, there is an effect of improving the configuration and image quality of the screen.

Claims (4)

A unit frame is divided into a plurality of subfields having different number of emission times in order to implement a gray level of an image, and the plurality of subfields are a sustain period for implementing a gray level according to the reset period, the address period, and the number of discharges of the sustain signal. In the plasma display apparatus, wherein the sustain signal is not applied to the subfields that do not cause discharge among the plurality of subfields, And a third gray level between the first gray level and the second gray level by applying the sustain signal having a predetermined number of discharges to at least one of the plurality of subfields in the first gray level. The method of claim 1, wherein the predetermined number of discharges, And a discharge cell of the sustain signal for implementing the first gray level and a number of discharges of the sustain signal for implementing the second gray level. The method of claim 1, wherein the third gradation, And an intermediate light amount between the light amount of the first gray level and the light amount of the second gray level. The method of claim 1, wherein the third gradation, And a sustain signal having an intermediate discharge number applied to one of subfields that does not cause discharge in the first grayscale, to a difference in the number of discharges applied to the first and second grayscales.

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