The present invention relates to a plasma display device, and more particularly, to a plasma display device in which the structure of a plurality of electrodes formed on a pad region surrounding an effective area displaying an image is improved to easily extend the contact area of the plurality of electrodes and a connecting member electrically coming into contact with the plurality of electrodes on the pad region.
A plasma display device includes a panel constructed in such a manner that a plurality of discharge cells are formed between a rear substrate on which a barrier is formed and a front substrate opposite to the rear substrate. The plasma display device selectively discharges the plurality of discharge cells according to an input image signal such that vacuum ultraviolet rays generated according to the discharge make a fluorescent material radiate to thereby display an image.
Generally, a plasma display panel applies a predetermined voltage to electrodes arranged in a discharge space to generate discharge such that plasma generated during gas discharge excites a fluorescent material to display an image including characters or graphic. The size of the plasma display panel can be easily increased and the weight and thickness thereof can be easily decreased. Further, the plasma display panel can provide a wide viewing angle and achieve full-color display and high luminance.
The plasma display device includes a driving circuit generating signals for driving the plasma display panel and connecting members for electrically connecting the panel and the driving circuit to supply the driving signals to a plurality of electrodes formed on the panel.
Recently, studies on a technique of extending the contact area of the plurality of electrodes and the connecting members of the plasma display device have been carried out.
According to an aspect of the present invention, there is provided a plasma display device comprising a plasma display panel on which a plurality of electrodes are formed, wherein at least one of the plurality of electrodes includes a line electrode, a connecting electrode and a pad electrode, and the line electrode, the connecting electrode and the pad electrode have different gradients.
According to another aspect of the present invention, there is provided a plasma display device comprising a plasma display panel on which a plurality of electrodes are formed, wherein the plurality of electrodes respectively include line electrodes, connecting electrodes and pad electrodes, and pad electrodes of first and second electrodes among the plurality of electrodes have different gradients.
According to another aspect of the present invention, there is provided a plasma display device comprising a plasma display panel on which a plurality of electrodes are formed, wherein at least one of the plurality of electrodes includes a line electrode, a connecting electrode and a pad electrode, and the length of the pad electrode is greater than the width of a contact region connected to a connecting member.
In the plasma display device according to the present invention, a plurality of electrodes electrically coming into contact with a connecting member on a pad region of the plasma display panel are sloped having predetermined gradients, and thus the electrodes can easily come into contact with the connecting member and the contact area of the electrodes and the connecting member can be increased. Further, a pad electrode pattern of the connecting member is also sloped according to the plurality of electrodes formed having gradients, and thus the size and area of the connecting member can be reduced and the manufacturing cost can be decreased.
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:
Hereinafter, an embodiment of the present invention will be described below with reference to the accompanying drawings.
Referring to
The sustain electrode pairs 11 and 12 respectively include transparent electrodes 1 la and 12a generally formed of indium-tin-oxide (ITO) and bus electrodes 11b and 12b. The bus electrodes 11b and 12b may be formed of a metal such as Ag or Cr or formed in a laminated structure of Cr/Cu/Cr or Cr/Al/Cr. The bus electrodes 11b and 12b are respectively formed on the transparent electrodes 11a and 12a and reduce voltage drop caused by the transparent electrodes 11a and 12a having high resistance.
In an embodiment of the present invention, the sustain electrode pairs 11 and 12 may be composed of only the bus electrodes 11b and 12b without having the transparent electrodes 11a and 12a. This structure can decrease the manufacturing cost of the plasma display panel because the transparent electrodes 11a and 12a are not used. In this structure, the bus electrodes 11b and 12b can be formed of various materials such as a photosensitive material in addition to the aforementioned materials.
A black matrix 15 having a light-shielding function that absorbs external light generated outside the upper substrate 10 to reduce reflection and a function of improving the purity and contrast of the upper substrate 10 is arranged between the scan electrode 11 and the sustain electrode 12.
In the current embodiment of the invention, the black matrix 15 is formed on the upper substrate 10 and may include a first black matrix 15 superposed on a barrier 21 and a second black matrix 11c and 12c formed between the transparent electrodes 11a and 12a and the bus electrodes 11b and 12b. Here, the first black matrix 15 and the second black matrix 11c and 12c that is also referred to as a black layer or a black electrode layer may be simultaneously formed and physically connected to each other. Otherwise, the first black matrix 15 and the second black matrix 11c and 12c may not be simultaneously formed and physically connected to each other.
The first black matrix 15 and the second black matrix 11c and 12c may be formed of the same material when they are physically connected to each other and formed of different materials when they are physically separated from each other.
An upper dielectric layer 13 and a protective layer 14 are sequentially formed on the upper substrate 10 on which the scan electrode 11 and the sustain electrode 12 are formed in parallel. The upper dielectric layer 13 has charged particles accumulated therein, which are generated according to discharge, and protects the sustain electrode pairs 11 and 12. The protective layer 14 protects the upper dielectric layer 13 from sputtering of charged particles generated during gas discharge and increases secondary electron emission efficiency.
Further, the protective layer 14 may be formed of MgO or Si—MgO. Here, the content of Si added to the protective layer 14 may be in the range of 60 PPM to 200 PPM based on weight percent.
The address electrodes 22 intersect the scan electrode 11 and the sustain electrode 12. Further, a lower dielectric layer 23 and the barrier 21 are formed on the lower substrate 20 on which the address electrodes 22 are formed.
In addition, a fluorescent layer 23 is formed on the surfaces of the lower dielectric layer 24 and the barrier 21. The barrier 21 includes vertical parts 21a and horizontal parts 21b arranged in an intersecting manner, physically segments a discharge space into discharge cells and prevents ultraviolet rays and visible rays generated due to discharge from leaking to neighboring discharge cells.
In an embodiment of the invention, the barrier 21 can have various structures other than the structure illustrated in
In the current embodiment of the invention, R, G and B discharge cells are arranged on the same line. However, the R, G and B discharge cells may be arranged in different forms. For example, the R, G and B discharge cells may be arranged in a triangular shape, which is a delta type. Further, the R, G and B discharge cells may have various polygonal shapes such as a square, a pentagon and a hexagon.
The fluorescent layer 23 radiates according to ultraviolet rays generated during gas discharge to emit one of red, green and blue visible lights. An inert mixed gas for discharge, such as He+Xe, Ne+Xe and He+Ne+Xe, is injected into the discharge space between the upper and lower substrates 10 and 20 and the barrier 21.
Referring to
The arrangement of electrodes, illustrated in
A unit frame can be segmented into a predetermined number of subfields, for example, eight subfields SF1 through SF8, to achieve time division gradation display. Further, the subfields SF1 through SF8 are respectively divided into reset periods (not shown), address periods A1 through A8 and sustain periods S1 through S8.
In the current embodiment of the invention, the reset period may be omitted from at least one of the plurality of subfields. For example, the reset period may exist only in the initial subfield or only in an intermediate subfield.
In the address periods A1 through A8, a display data signal is applied to address electrodes X and scan pulses are sequentially applied to scan electrodes Y.
In the sustain periods S1 through S8, a sustain pulse is alternately applied to the scan electrodes Y and sustain electrodes Z, and thus sustain discharge occurs in discharge cells in which wall charges are generated during the address periods A1 through A8.
The luminance of the plasma display panel is proportional to the number of sustain discharge pulses in the sustain discharge periods S1 through S8, included in the unit frame. If a single frame forming a signal image is represented by eight subfields and 256 gray-scales, 1, 2, 4, 8, 16, 32, 64 and 128 sustain pulses may be respectively allocated to the eight subfields. To obtain luminance corresponding to 133 gray-scales, cells are addressed to generate sustain discharge during first, third and eighth subfield periods.
The number of sustain discharges allocated to each subfield can be variably determined based on weights of subfields according to automatic power control (APC) stage. That is, although
Further, the number of sustain discharges allocated to each subfield can be variably changed in consideration of gamma characteristic or panel property. For example, gradation allocate to the fourth subfield can be reduced from 8 to 6 and gradation allocated to the sixth subfield can be increased from 32 to 64.
Each subfield can include a pre-reset period for forming positive wall charges on the scan electrodes Y and forming negative wall charges on the sustain electrodes Z, a reset period for initializing all the discharge cells of the plasma display panel by using distribution of the wall charges formed during the pre-reset period, an address period for selecting discharge cells, and a sustain period for sustaining discharge of the selected discharge cells.
The reset period includes a setup period and a setdown period. During the setup period, a ramp-up waveform is simultaneously applied to all the scan electrodes Y to generate minute discharge in all the discharge cells, and thus wall charges are generated. During the setdown period, a ramp-down waveform that falls at a positive voltage lower than the peak voltage of the ramp-up waveform is simultaneously applied to all the scan electrodes Y to generate erase discharge in all the discharge cells, and thus unnecessary charges among the wall charges generated according to setup discharge and space charges.
In the address period, a scan signal having a negative scan voltage Vsc is sequentially applied to the scan electrodes Y and, at the same time, a positive data signal is applied to the address electrodes X. Address discharge occurs according to a voltage difference between the scan signal and the data signal and a wall voltage generated during the reset period to select cells. To improve the efficiency of address discharge, a sustain bias voltage Vzb is applied to the sustain electrodes Z.
During the address period, the scan electrodes Y may be divided into at least two groups and scan signals may be sequentially supplied to the respective groups. Further, each of the groups may be divided into at least two sub-groups and scan signals may be sequentially supplied to the respective sub-groups. For example, the scan electrodes Y may be divided into a first group and a second group, scan signals may be sequentially supplied to scan electrodes belonging to the first group, and then scan signals may be sequentially supplied to scan electrodes belonging to the second group.
In an embodiment of the present invention, the plurality of scan electrodes Y may be divided into a first group including even-numbered scan electrodes and a second group including odd-numbered scan electrodes according to positions of the scan electrodes on the panel. In another embodiment of the present invention, the scan electrodes Y may be divided into a first group including scan electrodes located in the upper part of the panel and a second group including scan electrodes located in the lower part of the panel based on the center of the panel.
The scan electrodes belonging to the first group may be divided into a first sub-group having even-numbered scan electrodes and a second sub-group having odd-numbered scan electrodes or divided into a first group including scan electrodes located in the upper part of the first group and a second sub-group including scan electrodes located in the lower part of the first group based on the center of the first group.
In the sustain period, sustain pulse signals having a sustain voltage Vs are alternately applied to the scan electrodes and the sustain electrodes to generate sustain discharge in the form of surface discharge between neighboring scan electrode and sustain electrode.
The first or last sustain pulse signal among the sustain pulse signals alternately applied to the scan electrodes and the sustain electrodes during the sustain period may have a width greater than those of the other sustain pulse signals.
An erase period for erasing wall charges left on scan electrodes or sustain electrodes of on cells selected in the address period by generating weak discharge after the sustain discharge occurs may follow the sustain period.
The erase period may be included in all the subfields or in some of the subfields. It is preferable to apply an erase signal for the weak discharge to an electrode to which the last sustain pulse signal is not applied during the sustain period.
The erase signal may use a ramp signal, a low-voltage wide pulse, a high-voltage narrow pulse, an exponential signal or a half-sinusoidal pulse. Further, a plurality of pulses may be sequentially applied to the scan electrodes or the sustain electrodes to generate the weak discharge.
The operation of the plasma display panel may be divided into a power on sequence period and a normal operation period and driving signals provided during the power on sequence period and the normal operation period may have the same waveform or different waveforms if required.
That is, when the plasma display device is powered on, any image is not displayed on the plasma display panel and a power on sequence for preparing a normal operation of the plasma display panel is performed for a predetermined period of time or until a driving voltage supplied to the panel reaches a normal level. Then, an image is displayed on the plasma display panel according to driving signals supplied to the panel during the normal operation period.
Further, even before power supply to the plasma display device is cut, a power off sequence similar to the power on sequence may exist in order to smoothly end power supply to a driving circuit or the panel.
For instance, a display enable signal has a low level corresponding to a value “0” and thus a data signal is not applied to the panel for a predetermined time after power is supplied to the plasma display device. Accordingly, any image is not displayed on the plasma display panel. After a lapse of the predetermined time, the display enable signal has a high level corresponding to “1” and thus the data signal is applied to the panel and an image is displayed on the panel. Moreover, the display enable signal has a low level corresponding to “0” for a predetermined time before power supply to the plasma display device is ended, and thus any image is not displayed on the panel.
Referring to
Specifically, the PCB is connected to a plurality of driving integrated circuits (referred to as “driver ICs” for supplying driving signals to the plasma display panel 200 and the PCB and the plasma display panel 200 may be connected to each other through a connecting member, that is, a flexible printed circuit (FPC).
The filter 220 is located in front of the plasma display panel 200, shields electro-magnetic interference (EMI) and prevents external light from reflecting.
The back cover 230 envelops the backside of the plasma display panel 200. The bezel 240 is combined with the back cover 230 and protruded from the front side of the plasma display device to support the filter 220 while surrounding parts of the edge of the filter 220.
Though the plasma display device includes the filter 220 in the current embodiment of the invention, the filter 220 may be omitted. That is, an EMI pattern instead of the filter 220 may be formed on the plasma display panel 200 to shield EMI.
Referring to
Here, the pad region P2 is covered by the bezel (not shown) and electrically comes into contact with the plurality of electrodes (not shown) formed on the upper substrate 205 and a plurality of pad electrodes (not shown) included in a connecting member (not shown). Though
Referring to
At least one of the scan electrodes Y may include a line electrode, a connecting electrode and a pad electrode. The line electrode, the connecting electrode and the pad electrode may have different gradients. In this case, at least one of the scan electrodes Y may include a line electrode YL extended in the horizontal direction, a connecting electrode YC extended from the line electrode YL and sloped from the line electrode YL having a first gradient θ1, and a pad electrode YP extended from the connecting electrode YC and sloped from a line parallel with the line electrode YL having a second gradient θ2. In the current embodiment of the invention, a gradient is based on the line electrode or a line parallel with the line electrode. That is, the gradient corresponds to an angle from the line electrode or the line parallel with the line electrode.
The line electrode YL is formed on the effective area P1 and generates discharge according to a driving voltage supplied from the connecting member (not shown). The connecting electrode YC is formed on the pad region P2, extended from the line electrode YL and sloped having the first gradient θ1 and may not generate discharge according to the driving voltage. Further, the pad electrode YP is extended from the connecting electrode YC and sloped from the line parallel with the line electrode YL having the second gradient θ2. The pad electrode YP is formed on a contact region P2_1 which electrically comes into contact with the connecting member on the pad region P2. Here, the length L1 of the pad electrode YP is greater than the length L of the shorter side of the contact region P2_1.
The line electrode YL and the pad electrode YP are formed in parallel with each other, in general. In this case, the shape of the connecting member electrically coming into contact with the pad electrode YP is restricted by the shape of the pad electrode YP, and thus the size of the connecting member may unnecessarily increase and the manufacturing cost may also increase.
Further, the length of the pad electrode YP tends to decrease as the size of the bezel or the pad region P2 decreases. Accordingly, the contact area of the pad electrode is reduced, and thus poor products may be produced and productivity may be deteriorated.
According to the current embodiment of the invention, the line electrode YL, the connecting electrode YC and the pad electrode YP may have different gradients, as illustrated in
Further, even if the width of the contact region P2_1 decreases, the pad electrode YP is formed having a gradient, and thus the contact area and contact length of the pad electrode YP increase, as compared to a case that the pad electrode is formed in parallel with the line electrode YL. Accordingly, poor products can be improved and productivity can be increased.
Here, the angle between the connecting electrode YC and the pad electrode YP may be in the range of 110° to 150°. The gradient θ2 of the pad electrode YP, that is, the angle between the pad electrode YP and the line parallel with the line electrode YL, may be in the range of 10° to 40°. This is for the purpose of maintaining a distance between neighboring line electrodes YL greater than a predetermined value even if the number of scan electrodes Y increases and preventing defects such as short-circuit generated during a process.
Further, the gradient θ2 of the pad electrode YP may be 30° in order to prevent the scan electrodes Y from short-circuiting during a patterning process.
Here, the length L1 of the pad electrode YP superposed on the contact region P2_1 can be calculated using the length L of the shorter side of the contact region P2_1 and the cosine function of the second gradient θ2. Accordingly, it can be easily known that the length L1 of the pad electrode YP can be greater than the length L of the shorter side of the contact region P2_1.
That is, in the plasma display device according to the present invention, the length of the pad electrode is greater than the width of the contact region connected with the connecting member.
Further, the contact area of the pad electrode corresponds to the product of the length of the pad electrode and the width of the pad electrode, and thus an increase in the contact length is proportional to an increase in the contact area.
Moreover, a distance D1 between connecting electrodes YC of two neighboring scan electrodes Y may be identical to or narrower than a distance D2 between pad electrodes YP of the two neighboring scan electrodes Y. This is because the second gradient θ2 can be identical to or smaller than the first gradient θ1 for preparing for a increase in the width of the pad electrode.
Further, the scan electrodes Y are symmetrically arranged based on the center. If the scan electrodes Y are divided into a plurality of blocks, scan electrodes of each block can be symmetrically formed.
Though
That is, the widths of some of the pad electrodes may be widened in order to increase the contact area. Further, if there is a large difference among the gradients of the pad electrodes or connecting electrodes of the plurality of scan electrodes, a length difference among the pad electrodes or connecting electrodes may be generated because the electrodes are required to be formed in a predetermined area. In this case, the lengths of the connecting electrodes or pad electrodes may be varied to reduce a difference among line resistances of the electrodes so as to compensate for a line resistance difference.
Referring to
The second connecting part 124 of the connecting member (FPC) according to the present invention may be directly bonded to the PCB without using an additional connector. For example, the connecting member may be bonded to the PCB using an anisotropic conductive film (ACF). The ACF is an adhesive material having bidirectional insulation and conductivity in the thickness direction and corresponds to a tape on which conductive particles are dispersed.
The ACF can be placed between the connecting member and the PCB and heated or pressed to fix the connecting member onto the PCB and, simultaneously, electrically connect the connecting member with the PCB.
The first connecting part 122 is formed such that the pad electrodes Y_Pad are sloped having the second gradient θ2 to be overlapped with the pad electrodes YP of the scan electrodes Y. Accordingly, the size of the connecting member (FPC) can be reduced to smaller than the connecting member shown in
In the plasma display device according to the present invention, the scan electrodes and the pad electrodes are formed having predetermined angles, and thus the contact area of electrodes can be increased to cope with a reduction of the pad region, that is, the contact region, due to the bezel. Accordingly, horizontal flickering can be prevented.
While
In general, a plurality of scan electrodes are connected to multiple connecting members. Accordingly, a problem such as uneven luminance may generate due to a temperature variation according to positions of the scan electrodes in the entire area from the top and bottom of the panel and use of the scan electrodes. However, the present invention can provide most suitable electrode shapes without changing the electrodes of the effective area.
Referring to
Accordingly, a luminance difference between lines can be corrected by forming connecting electrodes or pad electrodes having different gradients.
Referring to
That is, the plasma display device according to the current embodiment of the invention includes a plasma display panel on which a plurality of electrodes are formed. The plurality of electrodes respectively include line electrodes YL, connecting electrodes YC and pad electrodes YP, and the gradient of the pad electrode of a first electrode of the plurality of electrodes is different from the gradient of the pad electrode of a second electrode of the plurality of electrodes.
The connecting electrodes YC and the pad electrodes YP can be designed such that they have various gradients and lengths, and thus the plurality of electrodes can have various line resistances and the line resistances can be corrected in various manners, as compared to the embodiment illustrated in
Specifically, pad electrodes of electrodes belonging to a first group, which are connected to a single connecting member, among the plurality of electrodes can be formed in such a manner that upper and lower pad electrodes are symmetrical. In this case, the gradients θ2a and θ2c of the pad electrodes are equal to each other.
Further, the gradient θ2b may be smaller than the gradient θ2a, as illustrated in
Moreover, the line electrode, the connecting electrode and the pad electrode of at least one of the first and second electrodes may have different gradients, as described above with reference to
Referring to
While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.
Number | Date | Country | Kind |
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10-2009-0038685 | May 2009 | KR | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/KR2009/006477 | 11/5/2009 | WO | 00 | 12/17/2010 |