KR20070076836A - Display device - Google Patents

Abstract

A display device is provided to obtain uniform luminance by increasing a contact area between a common electrode and a common voltage supply unit according to an increase of a distance from a driving voltage supply unit. A driving voltage supply unit is positioned on a first region of a non-display region which is extended in parallel to a gate line(121). A driving voltage line(145) receives a driving voltage from the driving voltage supply unit and is extended along an extension of a data line(141). A common voltage supply unit is positioned on a second region of the non-display region which is extended in parallel to the data line. A contact area between a common electrode and the common voltage supply unit is increased according to an increase of a distance from the driving voltage supply unit.

Description

Display {DISPLAY DEVICE}

1 is an equivalent circuit diagram of a display device according to a first embodiment of the present invention.

2 and 3 are layout views of a display device according to a first embodiment of the present invention.

4 is a view for explaining a display area and a non-display area in the display device according to the first embodiment of the present invention;

5 is a cross-sectional view taken along the line VV of FIG. 2,

FIG. 6 is a cross-sectional view taken along VI-VI of FIG. 2;

7 is a graph for describing a distribution of driving voltages according to positions in a display device according to a first embodiment of the present invention.

8 is a layout view of a display device according to a second exemplary embodiment of the present invention.

9 is a layout view of a display device according to a third exemplary embodiment of the present invention.

10 is a graph for describing a distribution of driving voltages according to positions in a display device according to a third exemplary embodiment of the present invention.

Explanation of Signs of Major Parts of Drawings

110: first insulating substrate 121: gate line

123: common voltage applying unit 125: driving voltage pad

126: driving voltage bar 141: data line

145: driving voltage line 180: organic layer

The present invention relates to a display device, and more particularly, to a display device having a display area in which gate lines and data lines intersect each other, and a non-display area surrounding the display area.

Among flat panel displays, organic light emitting diodes (OLEDs) have recently been in the spotlight due to advantages such as low voltage driving, light weight, wide viewing angle, and high speed response. OLEDs are classified into a passive matrix and an active matrix according to the driving method. The passive type has a simple manufacturing process, but the power consumption increases rapidly as the display area and resolution increase. Therefore, the passive type is mainly applied to small displays. Active type, on the other hand, has a complex manufacturing process but has the advantage of realizing a large screen and high resolution.

In the active OLED substrate, a plurality of thin film transistors are disposed in one pixel. Generally, at least two thin film transistors, such as a switching thin film transistor connected to a data line and a driving thin film transistor connected to a driving voltage line, are disposed.

The driving voltage line receives a driving voltage from the driving voltage supply part of one side of the substrate. However, the farther away from the driving voltage supply unit, the lower the driving voltage is, thereby reducing the luminance.

Accordingly, an object of the present invention is to provide a display device with a uniform luminance distribution.

An object of the present invention is a display device having a display area in which gate lines and data lines cross each other and a non-display area surrounding the display area, wherein the non-display area extends in parallel with the gate line. A driving voltage supply unit positioned in the first region; A driving voltage line receiving a driving voltage from the driving voltage supply unit and extending along the extension direction of the data line; A common voltage supply part positioned in a second area of the non-display area extending in parallel with the data line; It is achieved by including a common electrode in which the contact area with the common voltage supply is wider away from the driving voltage supply.

An extension of the common voltage supply part in the third area of the non-display area facing the first area with the display area therebetween is advantageous for increasing the contact area.

The driving voltage supply unit may be provided in plural numbers separated from each other by the gate pad.

The driving voltage supply unit may include a driving voltage bar extending in parallel with the gate line.

The common voltage supply unit and the common electrode may be in direct contact or may be connected through a bridge unit which connects the common voltage supply unit and the common electrode and is made of a transparent conductor.

An additional common voltage supply part is formed in a fourth area of the non-display area facing the second area with the display area therebetween, and the contact area of the common electrode and the additional common voltage supply part is the driving voltage. The further away from the supply, the better it is to achieve uniform brightness.

An additional driving voltage supply part is formed in a third area of the non-display area facing the first area with the display area therebetween, one end of the driving voltage line being connected to the driving voltage supply part, and the driving voltage line The other end of is connected to the additional drive voltage supply, which is advantageous for preventing the voltage change of the drive voltage line.

The display device may further include an organic emission layer formed in the display area.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

In various embodiments, like reference numerals refer to like elements, and like reference numerals refer to like elements in the first embodiment and may be omitted in other embodiments.

In the description, 'phase' means that another layer (membrane) is interposed or not interposed between the two layers (membrane), and 'just on' means that the two layers (membrane) are in contact with each other.

1 is an equivalent circuit diagram of a display device according to a first embodiment of the present invention.

1 is an equivalent circuit diagram of a pixel in a display device according to an exemplary embodiment of the present invention.

A plurality of signal lines are provided in one pixel. The signal line includes a gate line for transmitting a scan signal, a data line for transmitting a data signal, and a driving voltage line for transmitting a driving voltage. The data line and the driving voltage line are adjacent to each other and disposed side by side, and the gate line extends perpendicular to the data line and the driving voltage line.

Each pixel includes an organic light emitting element LD, a switching thin film transistor Tsw, a driving thin film transistor Tdr, and a capacitor C.

The driving thin film transistor Tdr has a control terminal, an input terminal, and an output terminal. The control terminal is connected to the switching thin film transistor Tsw, the input terminal is connected to a driving voltage line, and the output terminal is an organic light emitting diode ( LD).

The organic light emitting element LD has an anode connected to the output terminal of the driving thin film transistor Tdr and a cathode connected to the common voltage Vcom. The organic light emitting element LD displays an image by emitting light having a different intensity according to the output current of the driving thin film transistor Tdr. The current of the driving thin film transistor Tdr varies in magnitude depending on the voltage applied between the control terminal and the output terminal.

The switching thin film transistor Tsw also has a control terminal, an input terminal and an output terminal, the control terminal is connected to the gate line, the input terminal is connected to the data line, and the output terminal of the driving thin film transistor Tdr. It is connected to the control terminal. The switching thin film transistor Tsw transfers a data signal applied to the data line to the driving thin film transistor Tdr according to a scan signal applied to the gate line.

The capacitor C is connected between the control terminal and the input terminal of the driving thin film transistor Tdr. The capacitor C charges and maintains a data signal input to the control terminal of the driving thin film transistor Tdr.

The display device according to the first embodiment will be described in detail with reference to FIGS. 2 to 6 as follows. 2 and 3 are layout views of a display device according to a first embodiment of the present invention, FIG. 4 is a view for explaining a display area and a non-display area in the display device according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line VV of FIG. 2 and FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG. 2.

FIG. 2 illustrates a state in which the data driver 400, the gate driver 500, the driving voltage transmitter 611, and the common voltage transmitter 622 are excluded from FIG. 3. 5 and 6 illustrate only the driving transistor Tdr.

The display device 1 according to the first embodiment includes a first insulating substrate 110, a second insulating substrate 200, and a sealant 300 for bonding both substrates 110 and 200.

The first insulating substrate 110 includes a rectangular display area and a non-display area surrounding the display area.

First, the non-display area will be described.

The data pad 144 connected to the data driver 400 is provided in the first area above the display area among the non-display areas. The data pad 144 is connected to the data line 141 extending to the display area.

The data pads 144 are provided in plural numbers spaced apart at regular intervals, and the driving voltage pads 125 are positioned between the data pads 144. The driving voltage pad 125 receives a driving voltage from the data driver 400 through the driving voltage transfer unit 611.

Each driving voltage pad 125 is connected to a driving voltage bar 126 arranged in parallel with the gate line 121. The driving voltage bar 126 is connected to a driving voltage line 145 extending in parallel with the data line 141. In an embodiment, the driving voltage bar 126 and the driving voltage line 145 are formed of different layers, and the driving voltage bar 126 and the driving voltage line 145 are connected through the driving bridge 164 made of a transparent conductive material. It is. The driving voltage pads 125 and the driving voltage bars 126 form driving voltage applying units 125 and 126.

A gate pad 124 connected to the gate driver 500 is provided in the second region on the left side of the non-display area. The gate pad 124 is connected to the gate line 121 extending to the display area.

The gate pads 124 are provided in plural numbers spaced apart at regular intervals, and the common voltage applying unit 123 is positioned between the gate pads 124. The common voltage applying unit 123 receives a common voltage from the gate driver 500 through the common voltage transfer unit 622.

A portion (A of FIG. 5) of the common voltage applying unit 123 that does not overlap with the second insulating substrate 200 is exposed through the contact hole 154, and the portion A is a contact member made of a transparent conductive material. 162 is covering. The common voltage transfer unit 622 is connected to the portion A so that the common voltage applying unit 123 receives the common voltage.

A portion B of the common voltage applying unit 123 extending to an area overlapping the second insulating substrate 200 is exposed by the contact hole 153, and the portion B is made of a transparent conductive material. Member 163 is covering.

The common electrode 190 is in contact with the contact member 163 through the contact hole 174. Accordingly, the common electrode 190 and the common voltage applying unit 123 are connected to each other via the contact member 163. Here, the area of the contact area where each common voltage applying unit 123 and the common electrode 190 are in contact varies with distance from the driving voltage applying units 125 and 126, which will be described in detail later.

The common voltage applying unit 123 of the second region extends in the third region below the display region among the non-display regions. The common voltage applying unit 123 extending in the third region is connected to the common electrode 190 to apply a common voltage to the common electrode 190.

In the first embodiment, since there is no configuration for applying the driving voltage to the third region, a separate driving voltage transfer unit is not attached to the third region. Thus, the design of the display device is free.

No other pattern is provided in the fourth region to the right of the display region among the non-display regions.

The non-described data driver 400 includes a flexible circuit film 401, a data driver chip 402, and a data circuit board 403, and the gate driver 500 includes a flexible circuit film 501 and a gate driver chip ( 502 and a gate circuit board 503.

Next, the display area will be described.

The gate line 121 and the gate electrode 122 are formed on the first insulating substrate 110 made of an insulating material such as glass, quartz, ceramic, or plastic. The gate line 121 and the gate electrode 122 are formed from the same metal layer as the common voltage applying unit 123, the gate pad 124, the driving voltage pad 125, and the driving voltage bar 126 of the non-display area. The gate line 121 is connected to the gate pad 124.

The gate insulating layer 131 made of silicon nitride (SiNx) or the like is formed on the gate line 121 and the gate electrode 122.

The semiconductor layer 132 made of amorphous silicon and the ohmic contact layer 133 made of n + hydrogenated amorphous silicon heavily doped with n-type impurities are sequentially formed on the gate insulating layer 131 where the gate electrode 122 is disposed. Here, the ohmic contact layer 133 is separated from both sides of the gate electrode 122.

The data line 141, the source electrode 142, and the drain electrode 143 are formed on the ohmic contact layer 133 and the gate insulating layer 131. The source electrode 142 and the drain electrode 143 are separated around the gate electrode 122. The data line 141, the source electrode 142, and the drain electrode 143 are formed from the same metal layer as the driving voltage line 145 and the data pad 144 of the non-display area.

The passivation layer 151 is formed on the source electrode 142, the drain electrode 143, and the semiconductor layer 132 which is not covered. The passivation layer 151 may be made of silicon nitride (SiNx). The passivation layer 151 is partially removed to form the contact hole 152 exposing the drain electrode 143.

The pixel electrode 161 is formed on the passivation layer 151. The pixel electrode 161 is also called an anode and supplies holes to the organic layer 180. The pixel electrode 161 is made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO), and is connected to the drain electrode 143 through the contact hole 152. The pixel electrode 161 is formed from the same transparent conductive layer as the contact members 162 and 163 and the driving bridge portion 164 of the non-display area.

The partition wall 171 surrounding the pixel electrode 161 is formed on the pixel electrode 161 and the passivation layer 151. The partition wall 171 defines the pixel area by dividing the pixel electrodes 161. The partition wall 171 also serves to prevent the source electrode 142 and the drain electrode 143 of the thin film transistor Tdr from being short-circuited with the common electrode 190. The partition wall 171 may be formed of a photoresist having heat resistance and solvent resistance, such as an acrylic resin and a polyimide resin, or an inorganic material such as SiO 2 or TiO 2, and may have a two-layer structure of an organic layer and an inorganic layer. The barrier rib 171 is formed with a contact hole 174 exposing the contact member 163.

The organic layer 180 is formed on the pixel electrode 161 not covered by the partition wall 171. The organic layer 180 includes a hole injecting layer 181 and an organic light emitting layer 182. The illustrated organic layer 180 is manufactured by a wet method such as inkjet, and the present invention is applied to a case where the organic layer 180 is manufactured by a dry method such as thermal evaporation.

The hole injection layer 181 is made of a hole injection material such as poly (3,4-ethylenedioxythiophene) (PEDOT) and polystyrenesulfonic acid (PSS). The hole injection material is mixed with water to inkjet in an aqueous suspension state. Can be formed in a manner.

The organic light emitting layer 182 may also be formed by an inkjet method.

The holes transferred from the pixel electrode 161 and the electrons transferred from the common electrode 190 are combined in the organic emission layer 182 to become excitons, and then generate light in the process of deactivating the excitons.

The common electrode 190 is positioned on the barrier rib 171 and the organic emission layer 182. The common electrode 190 is also called a cathode and supplies electrons to the organic emission layer 182.

The sealant 300 is formed along the circumference of the display area and combines the first insulating substrate 110 and the second insulating substrate 200. The second insulating substrate 200 serves as a capping to prevent the organic layer 180 from being exposed to moisture or oxygen.

Although not shown, the second substrate 200 may further include a moisture absorbent to protect the organic layer 180 from moisture. The moisture absorbent may be provided in the non-display area.

The contact between the common voltage applying unit 123 and the common electrode 190 in the display device 1 according to the first exemplary embodiment will be described with reference to FIGS. 5 to 7. 7 is a graph for describing a distribution of driving voltages according to positions in the display device according to the first exemplary embodiment of the present invention.

The contact area of the common voltage applying unit 123 and the common electrode 190 increases as the distance from the driving voltage applying units 125 and 126 increases. That is, the contact hole 174 having a distance farther from the driving voltage applying parts 125 and 126 than the width (d1 of FIG. 5) of the contact hole 174 having a relatively close distance from the driving voltage applying parts 125 and 126. The width of d (d2 in FIG. 6) is larger.

The driving voltage applied to the driving voltage line 145 is changed into the pixel voltage through the thin film transistor Tdr and transferred to the pixel electrode 161. The current of the pixel voltage transferred to the pixel electrode 161 flows through the common electrode 190 to the common voltage applying unit 123 connected to the common electrode 190.

However, as the driving voltage line 145 moves away from the driving voltage applying units 125 and 126, the driving voltage decreases. That is, the voltage drops due to the resistive component that is applied while applying the driving voltage to each pixel (dashed line in FIG. 7). For this reason, the luminance decreases as it moves away from the driving voltage applying sections 125 and 126.

According to the present invention, the contact area between the common electrode 190 and the common voltage applying unit 123 increases as the distance from the driving voltage applying units 125 and 126 increases, thereby reducing the resistance of the current flow. As a result, the driving voltage drop is compensated for and the luminance becomes constant irrespective of the distance from the driving voltage applying units 125 and 126 (solid line in FIG. 7).

Unlike the above embodiment, the contact area between the common voltage applying unit 123 and the common electrode 190 may be adjusted by changing the size of the contact hole 153 exposing the common voltage applying unit 123. In addition, the common voltage applying unit 123 and the common electrode 190 may be in direct contact with each other.

A display device according to a second embodiment of the present invention will be described with reference to FIG. 8.

In the second embodiment of Fig. 8, an additional common voltage applying unit 123a is provided in the fourth area of the non-display area. As the additional common voltage applying unit 123a and the common electrode 190 move away from the driving voltage applying units 125 and 126, the contact area increases.

According to the second embodiment, the luminance of the driving voltage is compensated for on both sides of the display area, thereby making the luminance even more uniform.

A display device according to a third embodiment of the present invention will be described with reference to FIGS. 9 and 10. FIG. 9 is a layout view of a display device according to a third exemplary embodiment of the present invention, and FIG. 10 is a graph illustrating distribution of driving voltages according to positions in the display device according to the third exemplary embodiment of the present invention.

The display device according to the third embodiment shown in FIG. 9 includes an additional driving voltage supply unit 127 formed in the third area of the non-display area. One end of the driving voltage line 145 is connected to the driving voltage supply units 125 and 126, and the other end of the driving voltage line 145 is connected to the additional driving voltage supply unit 127. Since the driving voltage line 145 of the third embodiment receives the driving voltage at both ends, the driving voltage drop is relatively small, but the driving voltage is reduced at the center of the display area compared to both ends (dashed line in FIG. 10).

In the third embodiment, the contact area of the common voltage supplying part 123 and the common electrode 190 becomes wider toward the center of the display area, thereby reducing the driving voltage drop of the driving voltage line 145 (solid line in FIG. 10). .

Although some embodiments of the invention have been shown and described, those skilled in the art will recognize that modifications can be made to the embodiments without departing from the spirit or principles of the invention. . It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

As described above, the present invention provides a display device with a uniform luminance distribution.

Claims (8)

A display device having a display area in which gate lines and data lines intersect each other, and a non-display area surrounding the display area. A driving voltage supply part positioned in a first area of the non-display area extending in parallel with the gate line; A driving voltage line receiving a driving voltage from the driving voltage supply unit and extending along the extension direction of the data line; A common voltage supply part positioned in a second area of the non-display area extending in parallel with the data line; And a common electrode having a larger contact area with the common voltage supplyer as the distance from the driving voltage supply unit increases. The method of claim 1, And the common voltage supply unit is extended to a third region of the non-display region facing the first region with the display region therebetween. The method of claim 1, And a plurality of the driving voltage supply parts are separated from each other. The method according to any one of claims 1 to 3, And the driving voltage supply unit includes a driving voltage bar extending in parallel with the gate line. The method of claim 4, wherein And a bridge unit connecting the common voltage supply unit and the common electrode and formed of a transparent conductor. The method according to any one of claims 1 to 3, An additional common voltage supply unit is formed in a fourth region of the non-display region facing the second region with the display region interposed therebetween, And the contact area of the common electrode and the additional common voltage supply unit is wider as the contact area is farther from the driving voltage supply unit. The method according to any one of claims 1 to 3, An additional driving voltage supply unit is formed in a third region of the non-display region facing the first region with the display region therebetween, One end of the driving voltage line is connected to the driving voltage supply part, and the other end of the driving voltage line is connected to the additional driving voltage supply part. The method according to any one of claims 1 to 3, And an organic light emitting layer formed in the display area.

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