KR101712197B1 - Organic light emitting device - Google Patents

Abstract

An organic light emitting display includes a substrate, a plurality of first thin film transistors formed on the substrate, a plurality of pixel electrodes connected to the first thin film transistor, A common electrode formed on the light emitting member, and a plurality of light shielding films formed on the substrate and overlapping the pixel electrodes, respectively. Accordingly, deterioration of image quality caused by visual recognition of a vertical stripe pattern of a specific color due to an optical illusion is reduced, and the image quality of the organic light emitting display device is improved.

Organic light emission, OLED, poin line, vertical line, luminance, stripe

Description

TECHNICAL FIELD [0001] The present invention relates to an organic light emitting display device,

The present invention relates to an organic light emitting display.

2. Description of the Related Art In recent years, a cathode ray tube (CRT) has been replaced by a liquid crystal display (LCD) in accordance with such a demand.

However, a liquid crystal display device requires a separate backlight as a light-emitting device, and has many problems in terms of response speed and viewing angle.

As a display device capable of overcoming such a problem, an organic light emitting device (OLED) has attracted attention.

The organic light emitting display includes two electrodes and a light emitting layer disposed therebetween. Electrons injected from one electrode and holes injected from the other electrode are combined in the light emitting layer to form an exciton And the exciton emits light while emitting energy.

Since the organic light emitting display device is of a self-emission type and requires no separate light source, it is advantageous not only in power consumption but also in response speed, viewing angle, and contrast ratio.

The organic light emitting display may be divided into a passive matrix organic light emitting display (OLED) of a simple matrix type and an active matrix organic light emitting diode (OLED) of an active matrix type according to a method of driving the organic light emitting cells.

The active matrix organic light emitting display device includes a switching thin film transistor connected to a signal line and controlling a data voltage, a data voltage applied from the switching thin film transistor to a gate voltage, And a driving thin film transistor.

Accordingly, when the switching transistor is turned on by the signal transmitted through the signal line, the data voltage is applied to the gate voltage of the driving thin film transistor through the turned-on switching transistor, and the current The organic light emitting cells emit light.

At this time, by applying the data voltage according to the gradation, the amount of current flowing through the driving thin film transistor can be variously adjusted to determine the gradation, and the organic light emitting cell is divided into red, green, Thereby realizing a color screen.

The OLED display device is classified into a top emission type and a bottom emission type according to a direction of displaying an image. In the front emission type, a cathode electrode is formed of a transparent electrode material such as ITO or IZO The anode electrode is formed of an opaque conductive material, and in the backside discharge method, the electrode is disposed in the opposite manner. In addition, if necessary, the anode may be disposed on the upper side, and the entire surface emitting method may be adopted.

In general, there are various methods of arranging red, green, and blue pixels. Among them, a stripe type in which pixels of the same color are arranged in a column unit, a mosaic type in which pixels of red (R), green (G) and blue (B) A delta type in which red, green and blue pixels are arranged in a zigzag manner so that the pixels are alternately arranged in the column direction, and the like.

When the red, green, and blue pixels are arranged in a strip form, the pixel columns disposed at the leftmost and rightmost outermost portions of the organic light emitting display device are immediately adjacent to black non-display regions , The luminance of the pixels arranged in these portions appears to be relatively higher than the luminance of the pixels arranged in the other pixel columns. Particularly, when a high-luminance color such as white is displayed through a display area in which pixels are arranged, this illusion phenomenon becomes more conspicuous. As a result, the pixel colors of the pixel columns arranged in the left and right outermost portions of the organic light emitting display device are conspicuous to the user, and in particular, the colors of the pixel columns in which the white pixels are displayed are well visible, There arises a problem that the blue stripe is visible.

SUMMARY OF THE INVENTION It is an object of the present invention to improve the image quality of an OLED display.

According to an aspect of the present invention, an OLED display includes a substrate, a plurality of first thin film transistors formed on the substrate, a plurality of pixel electrodes connected to the first thin film transistors, A plurality of organic light emitting members, a common electrode formed on the light emitting member, and a plurality of light blocking films formed on the substrate and overlapping the pixel electrodes, respectively.

The pixel electrodes are arranged in a matrix, and the light shielding film is formed in the outermost pixel column of the pixel electrode.

The pixel columns in which the light shielding film is formed preferably emit the same light.

The light blocking film may overlap with about 20% to 40% of the aperture ratio of the pixel electrode.

The first thin film transistor includes a first control electrode formed on the substrate, a semiconductor overlapping the first control electrode, a first input and output electrode overlapping the semiconductor and facing the first control electrode, And the light blocking film may be formed of the same material in the same layer as the first control electrode.

The organic light emitting display device may be a bottom emission type.

The light shielding film may have a long shape in the longitudinal direction.

The OLED display according to the above feature may further include a first signal line, a second signal line intersecting the first signal line, a second input terminal connected to the first signal line, and a second control terminal connected to the second signal line And a second thin film transistor having a second output terminal connected to a second control terminal of the first thin film transistor.

According to this aspect of the present invention, the amount of light output from the pixels arranged in the pixel column causing an illusion phenomenon, such as that exhibiting relatively higher luminance than other pixel columns, is reduced by the light shielding film. Accordingly, deterioration of image quality caused by visual recognition of a vertical stripe pattern of a specific color due to an optical illusion is reduced, and the image quality of the organic light emitting display device is improved.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

In the drawings, the thickness is enlarged to clearly represent the layers and regions. Like parts are designated with like reference numerals throughout the specification. It will be understood that when an element such as a layer, film, region, plate, or the like is referred to as being "on" another portion, it includes not only the element directly over another element, Conversely, when a part is "directly over" another part, it means that there is no other part in the middle.

First, an organic light emitting display according to an embodiment of the present invention will be described in detail with reference to FIG.

1 is an equivalent circuit diagram of an OLED display according to an embodiment of the present invention.

1, the OLED display includes a plurality of signal lines 121, 171, and 172 and a plurality of pixels PX connected to the plurality of signal lines 121, 171, and 172 and arranged in a matrix form. do.

The signal line includes a plurality of gate lines 121 for transmitting a gate signal (or a scanning signal), a data line 171 for transmitting a data signal, and a plurality of driving voltage lines 172 for transmitting a driving voltage. The gate lines 121 extend substantially in the row direction, are substantially parallel to each other, and the data lines 171 and the driving voltage lines 172 extend in a substantially column direction and are substantially parallel to each other.

Each pixel PX includes a switching transistor Qs, a driving transistor Qd, a capacitor Cst, and an organic light emitting diode LD.

The switching transistor Qs has a control terminal, an input terminal and an output terminal. The control terminal is connected to the gate line 121, the input terminal is connected to the data line 171, Qd. The switching transistor Qs transfers a data signal applied to the data line 171 to the driving transistor Qd in response to a scanning signal applied to the gate line 121. [

The driving transistor Qd also has a control terminal, an input terminal and an output terminal. The control terminal is connected to the switching transistor Qs, the input terminal is connected to the driving voltage line 172, (LD). The driving transistor Qd passes an output current I _LD whose magnitude varies depending on the voltage applied between the control terminal and the output terminal.

The capacitor Cst is connected between the control terminal and the input terminal of the driving transistor Qd. This capacitor Cst charges the data signal applied to the control terminal of the driving transistor Qd and holds it even after the switching transistor Qs is turned off.

The organic light emitting diode LD has an anode connected to the output terminal of the driving transistor Qd and a cathode connected to the common voltage Vss. The organic light emitting diode LD emits light with different intensity according to the output current I _LD of the driving transistor Qd to display an image.

The switching transistor Qs is an n-channel field effect transistor (FET) and the driving transistor Qd is a p-channel field effect transistor. However, the channel type of the switching transistor Qs and the driving transistor Qd can be reversed, and both transistors Qs and Qd can be both n-channel field effect transistors or p-channel field effect transistors. Also, the connection relationship between the transistors Qs and Qd, the capacitor Cst, and the organic light emitting diode LD may be changed.

2 and 3, the organic light emitting diode display according to an embodiment of the present invention will be described in detail.

FIG. 2 is a layout diagram of an organic light emitting display according to an embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along a line III-III of the organic light emitting display of FIG.

A buffer layer 111 made of silicon nitride (SiNx), silicon oxide (SiOx) or the like is formed on an insulating substrate 110 made of transparent glass or plastic. The buffer layer 111 may have a double-layer structure.

The buffer layer 111 serves to prevent penetration of the impurity element and to flatten the surface, and can be omitted if necessary.

A plurality of pairs of first and second island-like semiconductor layers 151a and 151b made of polycrystalline silicon or the like are formed on the buffer layer 111. Each of the island-like semiconductor layers 151a and 151b includes a plurality of extrinsic regions including n-type or p-type conductive impurities and at least one intrinsic region substantially containing no conductive impurities.

In the first semiconductor 151a, the impurity region includes a first source and drain region 153a, 155a and an intermediate region 154a, which are doped with an n-type impurity Are separated from each other. The intrinsic region includes a first channel region (not shown) located between the impurity regions 153a and 155a, and the like.

In the second semiconductor 151b, the impurity region includes the second source and drain regions 153b and 155b, which are doped with the p-type impurity and are separated from each other. The intrinsic region includes a second channel region 154b located between the second source and drain regions 153b and 155b.

The impurity regions 153a, 155a, 153b and 155b of the first and second semiconductors 151a and 151b are doped with low concentration doping located between the channel regions 154a and 154b and the source and drain regions 153a and 155a, A lightly doped region (not shown). This lightly doped region can be replaced by an offset region that contains little impurities.

Alternatively, the impurity regions 153a and 155b of the first semiconductor 151a may be doped with a p-type impurity, or the impurity regions 153b and 155b of the second semiconductor 151b may be doped with an n-type impurity. Examples of the p-type conductive impurities include boron (B) and gallium (Ga). Examples of the n-type conductive impurities include phosphorus (P) and arsenic (As).

On the semiconductor layers 151a and 151b and the buffer layer 111, a gate insulating layer 140 made of silicon nitride or silicon oxide is formed.

A plurality of gate lines 121 including a first control electrode 124a, a plurality of second control electrodes 124b and a plurality of light blocking films 128 are formed on the gate insulating layer 140 A plurality of gate conductors are formed.

The gate line 121 transmits the gate signal and extends mainly in the horizontal direction. The first control electrode 124a extends downward from the gate line 121 and crosses the first semiconductor 151a, overlapping the first channel region 154a. Each of the gate lines 121 may include a wide-area end portion for connection with another layer or an external driving circuit. When a gate driving circuit (not shown) for generating a gate signal is integrated on the substrate 110, the gate line 121 may extend and be directly connected to the gate driving circuit.

The second control electrode 124b is separated from the gate line 121 and overlaps the second channel region 154b of the second semiconductor 151b. The second control electrode 124b has an extension 127 extending from the second control electrode 124b in a substantially rectangular shape.

The light shielding film 128 is formed only in the pixels arranged in the outermost pixel column on the left and right sides of the display area, and has a long island shape in the vertical direction. However, the present invention is not limited thereto. The light blocking film 128 may be formed on the right side, the upper side, the upper side, the upper side, the upper side or the lower side of the pixel, and may have various shapes such as an ellipse, a circle, . ≪ / RTI >

The gate conductors 121, 124b and 128 may be formed of a metal such as aluminum (Al) or an aluminum alloy, a metal such as silver or silver alloy, a copper-based metal such as copper or copper alloy, molybdenum ), A molybdenum-based metal such as a molybdenum alloy, chromium (Cr), tantalum (Ta), and titanium (Ti). However, they may have a multi-film structure including two conductive films (not shown) having different physical properties. One of the conductive films is made of a metal having a low resistivity, for example, an aluminum-based metal, a silver-based metal, or a copper-based metal to reduce signal delay and voltage drop. Alternatively, the other conductive film is made of a material having excellent physical, chemical, and electrical contact properties with other materials, particularly indium tin oxide (ITO) and indium zinc oxide (IZO), such as molybdenum metal, chromium, titanium, tantalum, A good example of such a combination is a chromium bottom film, an aluminum (alloy) top film, an aluminum (alloy) bottom film and a molybdenum (alloy) top film. However, the gate conductors 121, 124b, and 128 may be made of a variety of other metals or conductors.

The side surfaces of the gate conductors 121, 124b, and 128 are inclined with respect to the surface of the substrate 110, and the inclination angle thereof is preferably about 30 DEG to about 80 DEG.

An interlayer insulating film 160 is formed on the gate conductors 121, 124b, and 128. The interlayer insulating film 160 is made of an inorganic insulating material such as silicon nitride or silicon oxide, an organic insulating material, or a low dielectric constant insulating material. The dielectric constant of the organic insulating material and the low dielectric constant insulating material is preferably 4.0 or less, and examples of the low dielectric insulating material include a-Si: C: O, a-Si: O which is formed by plasma enhanced chemical vapor deposition (PECVD) : F and the like. The interlayer insulating layer 160 may have a photosensitivity among organic insulating layers, and the surface of the interlayer insulating layer 160 may be flat.

A plurality of contact holes 163a, 163b, 165a, and 165b that respectively expose the source and drain regions 153a, 153b, 155a, and 155b of the first and second semiconductors are formed in the interlayer insulating film 160 and the gate insulating film 140, A contact hole 164 for exposing the electrode 127 is formed.

A plurality of data lines 171, a plurality of driving voltage lines 172 and a plurality of first output electrodes 175a and a plurality of second output electrodes 175a are formed on the interlayer insulating layer 160. [ A plurality of data conductors including a plurality of data conductors 175b are formed.

The data line 171 transmits a data signal and extends mainly in the vertical direction and crosses the gate line 121. Each of the data lines 171 includes a plurality of first input electrodes 173a connected to the first source region 153a through a contact hole 163a and is connected to another layer or an external driving circuit It may include a wide end area for connection. When a data driving circuit (not shown) for generating a data signal is integrated on the substrate 110, the data line 171 may extend and be directly connected to the data driving circuit.

The driving voltage line 172 transmits the driving voltage and extends mainly in the vertical direction and crosses the gate line 121. Each of the driving voltage lines 172 includes a plurality of second input electrodes 173b connected to a second source region 153b through a contact hole 163b. The driving voltage line 172 extends toward the sustain electrode 127 and includes an extension 178 forming an upper electrode so that the extension 178 overlaps the sustain electrode 127 to form a storage capacitor.

The first output electrode 175a is separated from the data line 171 and the driving voltage line 172 and has a rectangular shape. The first output electrode 175a is connected to the sustain electrode 127 and the first drain region 155a through contact holes 164 and 165a, respectively.

The second output electrode 175b is separated from the data line 171, the driving voltage line 172 and the first output electrode 175a and has a rectangular shape. The second output electrode 175b has a contact hole 165b To the second drain region 155b.

The data conductors 171, 172, 175a, and 175b are preferably made of a refractory metal such as molybdenum, chromium, tantalum, and titanium or an alloy thereof, and may be formed of a refractory metal film (not shown) Lt; / RTI > (not shown). Examples of the multilayer structure include a double film of a chromium or molybdenum (alloy) lower film and an aluminum (alloy) upper film, a molybdenum (alloy) lower film, an aluminum (alloy) intermediate film and a molybdenum (alloy) upper film. However, the data conductors 171, 172, 175a, and 175b may be made of a variety of other metals or conductors.

It is preferable that the data conductors 171, 172, 175a, and 175b are inclined at an angle of about 30 to about 80 degrees with respect to the substrate 110 in the same manner as the gate conductors 121 and 121b.

A passivation layer 180 is formed on the data conductors 171, 172, 175a, and 175b. The protection film 180 is made of an inorganic material, an organic material, or a low dielectric constant insulating material.

The protective film 180 is formed with a plurality of contact holes 185 for exposing the second output electrode 175b. A plurality of contact holes (not shown) may be formed in the passivation layer 180 to expose the ends of the data lines 171. The passivation layer 180 and the interlayer insulating layer 160 may be formed with a plurality of contact holes A plurality of contact holes (not shown) may be formed.

A plurality of pixel electrodes 190 are formed on the passivation layer 180. The pixel electrode 190 is electrically connected to the second output electrode 175b through the contact hole 185 and may be formed of a transparent conductive material such as ITO or IZO or a reflective metal such as aluminum, have.

A plurality of contact assistants (not shown) or a connecting member (not shown) may be formed on the passivation layer 180. The gate lines 121 and the data lines 171, Lt; / RTI >

A partition 361 is formed on the passivation layer 180. The barrier rib 361 surrounds the periphery of the pixel electrode 190 to define an opening 365 and is made of an organic insulating material or an inorganic insulating material. The barrier ribs 361 may also be made of a photosensitizer containing a black pigment. In this case, the barrier ribs 361 serve as light shielding members, and the forming process is simple.

An organic light emitting member 370 is formed in the opening 365 on the pixel electrode 190 defined by the barrier rib 361. A part of the organic light emitting member 370 overlaps with the light shielding film 128 through the pixel electrode 190. At this time, the overlapping size of the organic light emitting member 370 and the light shielding film 128 may be about 20 to 40%, preferably about 30%, of the size of the opening of the pixel electrode 190.

The organic light emitting member 370 is made of an organic material that uniquely emits any one of primary colors such as red, green, and blue. The organic light emitting display displays a desired image with a spatial sum of the primary color light emitted by the organic light emitting members 370. In the organic light emitting display according to the present embodiment, the organic light emitting member 370 of a pixel located in the same pixel column is made of an organic material that emits the same light, and the organic light emitting member 370 of a pixel located in two adjacent pixel columns, Pixel colors are arranged in a stripe form made of an organic material emitting different light.

When the pixels are arranged in a stripe form, the organic light emitting member 370 of the pixel array formed on the left side of the display region is made of an organic material that emits red light, and the organic light emitting member 370 are made of organic materials that emit blue light, but are not limited thereto. However, the OLED display device may be arranged such that pixel colors are different from each other except for the stripe.

The organic light emitting member 370 may have a multi-layer structure including an auxiliary layer (not shown) for improving light emission efficiency of the light emitting layer in addition to a light emitting layer (not shown). The sub-layer includes an electron transport layer (not shown) and a hole transport layer (not shown) for balancing electrons and holes and an electron injection layer (not shown) for enhancing the injection of electrons and holes an electron injecting layer (not shown) and a hole injecting layer (not shown).

A common electrode 270 is formed on the organic light emitting member 370. The common electrode 270 receives a common voltage Vss and is made of a transparent conductive material such as ITO or IZO or a reflective metal containing calcium (Ca), barium (Ba), magnesium (Mg), aluminum .

In this organic light emitting display device, the first semiconductor 151a, the first control electrode 124a connected to the gate line 121, the first input electrode 173a connected to the data line 171, The output electrode 175a constitutes a switching thin film transistor Qs and the channel of the switching thin film transistor Qs is formed in the channel regions 154a1 154a2 of the first semiconductor 151a. A second control electrode 124b connected to the first output electrode 175a, a second input electrode 173b connected to the driving voltage line 172, and a pixel electrode 190 connected to the second semiconductor 151b, The second output electrode 175b is a driving TFT Qd and the channel of the driving thin film transistor Qd is formed in a channel region 154b of the second semiconductor 151b. The pixel electrode 190 may be an anode and the common electrode 270 may be a cathode. Alternatively, the pixel electrode 190, the organic light emitting member 370 and the common electrode 270 may be organic light emitting diodes, The electrode 190 serves as the cathode, and the common electrode 270 serves as the anode. The sustain electrodes 127 overlapping each other and the extension portion 178 of the drive voltage line 172 constitute a storage capacitor Cst.

The OLED display emits light toward the bottom of the substrate 110 to display an image. Accordingly, the OLED display according to the present embodiment includes a transparent pixel electrode 190 and an opaque common electrode 270, and a bottom emission type organic electroluminescent display device for displaying an image in a downward direction of the substrate 110, Emitting display device.

When the pixel colors are arranged in a stripe shape, the pixels of the pixel column disposed at the leftmost and rightmost outermost sides of the display area have their own colors, for example, red and blue. Even if the same data voltage is applied, a visual illusion occurs as if the luminance is relatively higher than the pixels of the other pixel columns.

In order to solve the problem that the colors of the pixels arranged at the outermost left and right sides are displayed as vertical stripes due to the optical illusion, the brightness of the pixel columns arranged at the outermost left and right sides should be lower than the brightness of the other pixel columns.

For this purpose, when the pixel aperture ratios of the pixel rows arranged at the left and right outermost sides of the display region are designed to be smaller than the pixel aperture ratios of the other pixel columns, the current density applied to the pixels increases, The generation rate and the like are increased, which causes a problem that the deterioration speed of the organic light emitting member 370 is accelerated.

However, in the embodiment of the present invention, as described above, the light blocking film 128 overlapping the organic light emitting member 370 is formed in the leftmost and rightmost outermost pixel columns of the display region, and the light blocking film 128 Of the pixel electrode 190 is approximately 20% to 40% of the aperture ratio of the pixel electrode 190, a part of the light generated by the organic light emitting member 370, for example, About 20% to about 40% is blocked by the light blocking film 128 and is not outputted downward of the substrate 110.

Therefore, the luminance of light output from the pixels of the outermost pixel columns on the left and right sides of the display area becomes lower than the luminance of light output from the pixels of the other pixel columns. As a result, without changing the size of the opening 365 of the pixel electrode 190 defined by the barrier ribs 361, the brightness of a pixel positioned at a desired pixel, for example, the leftmost and rightmost pixel columns of the display region is lowered . This reduces the optical phenomenon in which the colors of the pixels arranged in the leftmost and rightmost pixel columns on the left and right sides of the display region are perceptibly recognized without causing deterioration of the pixels.

Meanwhile, the first and second semiconductors 151a and 151b may be amorphous silicon. In this case, there is no separate impurity region in the first and second semiconductors 151a and 151b. A resistive contact member made of n + hydrogenated amorphous silicon having a high concentration of n-type impurity doped between the first and second semiconductors 151a and 151b and the data conductors 171, 173b, 175a, and 175b ).

The control electrodes 124a and 124b and the light shielding film 128 of the switching transistor Qs and the driving transistor Qd may be disposed below the first and second semiconductors 154a and 154b, Are located between the first and second semiconductors 154a and 154b and the control electrodes 124a and 124b and the light shielding film 128. [ At this time, the data conductors 171, 172, 173b, and 175b may be positioned directly above the gate insulating layer 140. [

In addition, the data conductors 171, 172, 173b, and 175b are located below the first and the second semiconductor layers 154a and 154b and are in electrical contact with the semiconductors 154a and 154b thereon.

Although the embodiment of the present invention has been described on the basis of the active matrix organic light emitting diode display device having a pixel structure having two transistors and one capacitor, the present invention is not limited to this, and a pixel structure including three or more transistors and two or more capacitors The present invention is of course applicable to organic light emitting display devices of other structures.

Further, the present invention can be applied to organic light emitting display devices in which pixel colors are arranged in other shapes, in addition to stripe type organic light emitting display devices.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

1 is an equivalent circuit diagram of an OLED display according to an embodiment of the present invention.

2 is a layout diagram of an OLED display according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view of the organic light emitting diode display of FIG. 2 taken along line III-III.

Claims (9)

Board, A plurality of first thin film transistors formed on the substrate, A plurality of transparent pixel electrodes connected to the plurality of first thin film transistors and arranged in a matrix, A plurality of organic light emitting members arranged on the plurality of transparent pixel electrodes, An opaque common electrode disposed on the plurality of organic light emitting members, And a plurality of light shielding films each having a island shape extending along the longitudinal direction so as to overlap only the pixel electrodes disposed on the leftmost and rightmost outermost pixel columns of the display region among the plurality of transparent pixel electrodes, Each of the plurality of first thin film transistors A first control electrode disposed on the gate insulating film so as to overlap with the semiconductor; an interlayer insulating film covering the first control electrode; and a second interlayer insulating film covering the first interlayer insulating film, An input electrode disposed on the insulating film and connected to the source region of the semiconductor; and an output electrode disposed on the interlayer insulating film and connected to the drain region of the semiconductor, Wherein the light blocking film is formed of the same material in the same layer as the first control electrode, The pixel column in which the light blocking film is formed emits the same light, Wherein the light blocking film overlaps with 20% to 40% of the aperture ratio of the pixel electrode. delete delete delete delete The method of claim 1, Wherein the organic light emitting display is a bottom emission type organic light emitting display. delete The method of claim 1, A first signal line, A second signal line crossing the first signal line, A second thin film transistor having a second input terminal connected to the first signal line, a second control terminal connected to the second signal line, and a second output terminal connected to a second control terminal of the first thin film transistor, Further comprising a transistor. The method of claim 1, Wherein the light shielding film is formed of a multi-film structure including two conductive films having different physical properties.

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