JP2007115622A - Organic electroluminescent display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress generation of an organic EL element which is unable to emit light due to slippage of relative positions of a luminous layer and a pixel electrode and suppress color shifting due to partial overlapping of the neighboring luminous layers. <P>SOLUTION: The organic EL display device is constructed equipped with a first organic EL element which includes a luminous layer EMT1 in an active layer and emits light by a small voltage, and a second organic EL element which includes a luminous layer EMT2 having different emitting color from that of the luminous layer EMT1 in the active layer and emits light by a larger voltage. In this case, the difference L<SB>B</SB>1-L<SB>A</SB>1 between the dimension L<SB>B</SB>1 along X direction of the luminous layer EMT1 and the dimension L<SB>A</SB>1 along the X direction of a portion P1 in contact with the active layer of the pixel electrode included in the first organic EL element is smaller than the difference L<SB>B</SB>2-L<SB>A</SB>2 between the dimension L<SB>B</SB>2 along X direction of the luminous layer EMT2 and the dimension L<SB>A</SB>2 along the X direction of a portion P2 in contact with the active layer of the pixel electrode included in the second organic EL element. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an organic electroluminescence (EL) display device.

  Many organic EL display devices capable of displaying a color image include organic EL elements whose emission colors are red, green, and blue. In these organic EL elements, the materials of the light emitting layer are different from each other. Therefore, for example, when a vacuum deposition method is used, the light emitting layer is formed for each light emission color using a mask.

  In this method, an organic EL element that cannot emit light may be generated due to a shift in the relative position between the light emitting layer and the pixel electrode. Therefore, in this method, in consideration of the alignment accuracy between the mask and the substrate and the thermal expansion of the mask, the material of the light emitting layer is generally deposited in a region wider than the region where it is necessary to form the light emitting layer. Is. However, when such a configuration is adopted, adjacent light emitting layers are likely to partially overlap. If the light emission colors of the partially overlapping light emission layers are different from each other, the light emission color of the organic EL element including these light emission layers may be shifted from the color to be displayed.

  The object of the present invention is to suppress the generation of an organic EL element that cannot emit light due to a shift in the relative position between the light emitting layer and the pixel electrode, and further, the adjacent light emitting layers partially overlap each other. It is to suppress color misregistration.

According to the first aspect of the present invention, an insulating substrate is disposed adjacent to the insulating substrate, each of which is disposed on the insulating substrate, a counter electrode facing the pixel electrode, and an intervening therebetween. And a first organic EL element having an active layer including a light emitting layer, and the first organic EL element has a light emitting color different from that of the second organic EL element. In addition, the light emitting layer emits light at a voltage smaller than that of the second organic EL element, and the dimension L _B 1 along the arrangement direction of the first and second organic EL elements of the light emitting layer included in the first organic EL element. And the dimension L _A 1 along the arrangement direction of the first portion in contact with the active layer of the pixel electrode included in the first organic EL element L _B 1−L _A 1 wherein the dimensions L _B 2 of the organic EL element along said direction of arrangement of the light emitting layer containing the The smaller compared to the difference L _B 2-L _A 2 of the second organic EL element dimensions L _A 2 along the arrangement direction of the second part in contact with the active layer of the pixel electrode, including the A characteristic organic EL display device is provided.

According to the second aspect of the present invention, an insulating substrate is disposed adjacent to the insulating substrate, each of which is disposed on the insulating substrate, a counter electrode facing the pixel electrode, and an intervening therebetween. And first to third organic EL elements each having an active layer including a light emitting layer, and the first organic EL element is adjacent to the third organic EL element with the second organic EL element interposed therebetween. In addition, the first to third organic EL elements have different emission colors from the light emitting layer, and the first organic EL element emits light with a voltage lower than that of the second organic EL element, and the second organic EL element emits light. The EL element emits light at a voltage lower than that of the third organic EL element, and the dimension L _B along the arrangement direction of the first and second organic EL elements of the light emitting layer included in the first organic EL element. 1 and the pixel electrode included in the first organic EL element Serial difference L _B 1-L _A 1 with dimensions L _A 1 along said array direction of the first portion in contact with the active layer, the arrangement direction of the light-emitting layer and the second organic EL element comprises the difference L _B 2-L _a between the dimension L _a 2 along the arrangement direction of the second part in contact with the active layer of the pixel electrode, wherein the dimension L _B 2 second organic EL element comprises along The difference L _B 2−L _A 2 is smaller than 2 and includes the dimension L _B 3 along the arrangement direction of the light emitting layer included in the third organic EL element and the third organic EL element. the organic EL display, wherein the smaller compared to the difference L _B 3-L _a 3 with dimensions L _a 3 along the arrangement direction of the third portion in contact with the active layer of the pixel electrode An apparatus is provided.

  According to the present invention, it is possible to suppress the generation of an organic EL element that cannot emit light due to a shift in the relative position between the light emitting layer and the pixel electrode, and further, the color caused by the overlapping of adjacent light emitting layers. The shift can be suppressed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same referential mark is attached | subjected to the component which exhibits the same or similar function, and the overlapping description is abbreviate | omitted.

  FIG. 1 is a plan view schematically showing a display device according to one embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing an example of a structure that can be employed in the display device of FIG. FIG. 3 is a plan view schematically showing an example of the arrangement of light emitting layers that can be employed in the display device of FIG.

  In FIG. 2, the display device is drawn such that its display surface, that is, the front surface or the light emitting surface faces downward, and the back surface faces upward. In FIG. 3, a region TPL indicates a region assigned to a triplet composed of three pixels having different emission colors.

  The display device of FIG. 1 is a bottom emission organic EL display device that employs an active matrix driving method. This organic EL display device includes a display panel DP, a video signal line driver XDR, and a scanning signal line driver YDR.

  As illustrated in FIGS. 1 and 2, the display panel DP includes an insulating substrate SUB such as a glass substrate, for example.

On the substrate SUB, as shown in FIG. 2, an undercoat layer UC is formed. For example, the undercoat layer UC is formed by laminating a SiN _x layer and a SiO _x layer in this order on the substrate SUB.

  On the undercoat layer UC, a semiconductor pattern made of, for example, polysilicon containing impurities is formed. A part of this semiconductor pattern is used as the semiconductor layer SC of FIG. In the semiconductor layer SC, impurity diffusion regions used as a source and a drain and a channel disposed between the source and the drain are formed. Further, another part of the semiconductor pattern is used as a lower electrode of a capacitor C described later. The lower electrodes are arranged corresponding to pixels PX1 to PX3 described later.

  Note that the pixels PX1 to PX3 are arranged in this order in the X direction to form a triplet. In the display area, the triplets are arranged in the X direction and the Y direction. That is, in the display area, a pixel column in which the pixels PX1 are arranged in the Y direction, a pixel column in which the pixels PX2 are arranged in the Y direction, and a pixel column in which the pixels PX3 are arranged in the Y direction are arranged in this order in the X direction. In addition, these three pixel columns are repeatedly arranged in the X direction.

  The semiconductor pattern is covered with the gate insulating film GI shown in FIG. The gate insulating film GI can be formed using, for example, TEOS (tetraethyl orthosilicate).

  On the gate insulating film GI, the scanning signal lines SL1 and SL2 shown in FIG. 1 are formed. The scanning signal lines SL1 and SL2 each extend in the X direction and are alternately arranged in the Y direction. The scanning signal lines SL1 and SL2 are made of, for example, MoW.

  An upper electrode of the capacitor C is further disposed on the gate insulating film GI. The upper electrode is arranged corresponding to the pixels PX1 to PX3, and faces the lower electrode. The upper electrode is made of, for example, MoW and can be formed in the same process as the scanning signal lines SL1 and SL2.

  The scanning signal lines SL1 and SL2 intersect the semiconductor layer SC. The intersection of the scanning signal line SL1 and the semiconductor layer SC constitutes the switching transistor SWa shown in FIGS. 1 and 2, and the intersection of the scanning signal line SL2 and the semiconductor layer SC is the switching transistor SWb shown in FIG. SWc is configured. Further, the lower electrode, the upper electrode, and the insulating film GI interposed therebetween constitute the capacitor C shown in FIG. 1, and the intersection of the extended portion of the upper electrode and the semiconductor layer SC is shown in FIG. A drive transistor DR is configured.

  In this example, the drive transistor DR and the switching transistors SWa to SWc are top-gate p-channel thin film transistors. Further, the portion indicated by reference numeral G in FIG. 2 is the gate of the switching transistor SWa.

The gate insulating film GI, the scanning signal lines SL1 and SL2, and the upper electrode are covered with an interlayer insulating film II shown in FIG. The interlayer insulating film II is made of, for example, SiO _x deposited by a plasma CVD method.

  On the interlayer insulating film II, the video signal line DL and the power supply line PSL shown in FIG. 1 are formed. As shown in FIG. 1, each video signal line DL extends in the Y direction and is arranged in the X direction. For example, each of the power supply lines PSL extends in the Y direction and is arranged in the X direction.

  On the interlayer insulating film II, the source electrode SE and the drain electrode DE shown in FIG. 2 are further formed. The source electrode SE and the drain electrode DE connect elements in each of the pixels PX1 to PX3.

  The video signal line DL, the power supply line PSL, the source electrode SE, and the drain electrode DE have, for example, a three-layer structure of Mo / Al / Mo. These can be formed in the same process.

The video signal line DL, the power supply line PSL, the source electrode SE, and the drain electrode DE are covered with a passivation film PS shown in FIG. The passivation film PS is made of, for example, SiN _x .

  On the passivation film PS, the pixel electrodes PE shown in FIG. 2 are arranged corresponding to the pixels PX1 to PX3. Each pixel electrode PE is connected to the drain electrode DE through a contact hole provided in the passivation film PS, and this drain electrode is connected to the drain of the switching transistor SWa.

  In this example, the pixel electrode PE is a light-transmitting front electrode. Further, the pixel electrode PE is an anode in this example. As a material of the pixel electrode PE, for example, a transparent conductive oxide such as ITO (indium tin oxide) can be used.

  A partition insulating layer PI shown in FIG. 2 is further formed on the passivation film PS. In the partition insulating layer PI, a through hole is provided at a position corresponding to the pixel electrode PE, or a slit is provided at a position corresponding to a column formed by the pixel electrode PE. Here, as an example, the partition insulating layer PI is provided with a through hole at a position corresponding to the pixel electrode PE.

  The partition insulating layer PI is, for example, an organic insulating layer. The partition insulating layer PI can be formed using, for example, a photolithography technique.

  On the pixel electrode PE, an organic layer ORG including a light emitting layer is formed as an active layer. The light emitting layer is, for example, a thin film containing a luminescent organic compound whose emission color is red, green, or blue. In FIG. 2, only the light-emitting layer is depicted as the organic layer ORG. However, in addition to the light-emitting layer, the organic layer ORG includes a hole injection layer, a hole transport layer, a hole blocking layer, an electron transport layer, an electron An injection layer and the like can be further included.

  The members indicated by reference numerals EMT1 to EMT3 in FIG. 3 are light emitting layers included in the pixels PX1 to PX3, respectively. The light emitting layers EMT1 to EMT3 have different emission colors.

  The partition insulating layer PI and the organic layer ORG are covered with the counter electrode CE. In this example, the counter electrode CE is an electrode connected to each other between the pixels PX1 to PX3, that is, a common electrode. In this example, the counter electrode CE is a cathode and a light-reflecting back electrode. The counter electrode CE is electrically connected to an electrode wiring (not shown) formed on the same layer as the video signal line DL through, for example, a contact hole provided in the passivation film PS and the partition insulating layer PI. It is connected. Each organic EL element OLED includes a pixel electrode PE, an organic layer ORG, and a counter electrode CE.

  Each of the pixels PX1 to PX3 includes a drive transistor DR, switching transistors SWa to SWc, an organic EL element OLED, and a capacitor C as shown in FIG. As described above, in this example, the drive transistor DR and the switching transistors SWa to SWc are p-channel thin film transistors.

  The drive transistor DR, the switching transistor SWa, and the organic EL element OLED are connected in series in this order between the first power supply terminal ND1 and the second power supply terminal ND2. In this example, the power supply terminal ND1 is a high potential power supply terminal, and the power supply terminal ND2 is a low potential power supply terminal.

  The gate of the switching transistor SWa is connected to the scanning signal line SL1. The switching transistor SWb is connected between the video signal line DL and the drain of the drive transistor DR, and its gate is connected to the scanning signal line SL2. The switching transistor SWc is connected between the drain and gate of the driving transistor DR, and the gate is connected to the scanning signal line SL2.

  The capacitor C is connected between the gate of the driving transistor DR and the constant potential terminal ND1 '. In this example, the constant potential terminal ND1 'is connected to the power supply terminal ND1.

  A video signal line DL is connected to the video signal line driver XDR. In this example, a power supply line PSL is further connected to the video signal line driver XDR. The video signal line driver XDR outputs a current signal as a video signal to the video signal line DL and supplies a power supply voltage to the power supply line PSL.

  Scanning signal lines SL1 and SL2 are connected to the scanning signal line driver YDR. The scanning signal line driver YDR outputs voltage signals as first and second scanning signals to the scanning signal lines SL1 and SL2, respectively.

  When an image is displayed on this organic EL display device, for example, each of the scanning signal lines SL1 and SL2 is line-sequentially driven. That is, the pixels PX1 to PX3 are scanned (selected) for each row. The writing operation is performed in the selection period in which the pixels PX1 to PX3 are selected, and the display operation is performed in the non-selection period.

In the selection period in which the pixels PX1 to PX3 in a certain row are selected, first, the scanning signal line driver opens the switching transistor SWa to the scanning signal line SL1 to which the previous pixels PX1 to PX3 are connected (set to a non-conductive state). The scanning signal is output as a voltage signal, and subsequently, the scanning signal that closes the switching transistors SWb and SWc (sets the conductive state) to the scanning signal line SL2 to which the previous pixels PX1 to PX3 are connected is output as the voltage signal. In this state, the video signal line driver outputs the video signal to the video signal line DL as a current signal (write current) I _sig , and the gate-source voltage V _gs of the drive transistor DR is changed to the previous video signal I _sig. Set to a size corresponding to. Thereafter, a scanning signal for opening the switching transistors SWb and SWc is output as a voltage signal from the scanning signal line driver to the scanning signal line SL2 to which the previous pixels PX1 to PX3 are connected, and then the previous pixels PX1 to PX3 are connected. A scanning signal for closing the switching transistor SWa is output to the scanning signal line SL1 as a voltage signal. This ends the selection period.

In the non-selection period, the switching transistor SWa remains closed and the switching transistors SWb and SWc remain open. In the non-selection period, a drive current I _drv having a magnitude corresponding to the gate-source voltage V _gs of the drive transistor DR flows through the organic EL element OLED. The organic EL element OLED emits light with a luminance corresponding to the magnitude of the drive current I _drv .

This organic EL display device can be manufactured, for example, by the following method.
First, a structure in which the counter electrode CE and the organic layer ORG are removed from the display panel DP described above, that is, an array substrate is prepared.

  Next, each layer included in the organic layer ORG is formed on the pixel electrode PE by a vacuum deposition method. Of the layers included in the organic layer ORG, the light emitting layers EMT1 to EMT3 are sequentially formed by a vacuum deposition method using a mask.

  Thereafter, the counter electrode CE is formed on the organic layer ORG. Further, the organic EL element OLED is sealed, and the video signal line driver XDR and the scanning signal line driver YDR are mounted on the display panel DP. As described above, the organic EL display device of FIG. 1 is obtained.

  FIG. 4 is a graph showing an example of voltage luminance characteristics of the organic EL element. In the figure, the horizontal axis indicates the voltage applied between the pixel electrode PE and the counter electrode CE, and the vertical axis indicates the luminance of the organic EL element OLED. Further, curves VL1 to VL3 indicate voltage luminance characteristics of the organic EL elements OLED included in the pixels PX1 to PX3, respectively.

  In the example illustrated in FIG. 4, the organic EL element OLED included in the pixel PX1 emits light at a voltage lower than that of the organic EL element OLED included in the pixel PX2, and the organic EL element OLED included in the pixel PX2 includes the organic EL included in the pixel PX3. It emits light with a smaller voltage compared to the element OLED. That is, the organic EL element OLED included in the pixel PX1 has a lower emission start voltage than the organic EL element OLED included in the pixel PX2.

  In this case, when the structures of FIGS. 2 and 3 are employed in the light emitting layers EMT1 and EMT2, it is possible to suppress the generation of an organic EL element OLED that cannot emit light due to a relative positional shift between the light emitting layer EMT2 and the pixel electrode PE. can do. In addition, it is possible to suppress color misregistration caused by the light emitting layer EMT1 and the light emitting layer EMT2 partially overlapping.

  FIG. 5 is a plan view schematically showing the arrangement of the light emitting layers of an organic EL display device according to a comparative example. FIG. 6 is a plan view schematically showing an example of a state in which the relative positions of the light emitting layer and the pixel electrode are shifted in the structure of FIG. FIG. 7 is a plan view schematically showing another example of a state in which the relative positions of the light emitting layer and the pixel electrode are shifted in the structure of FIG.

In FIG. 5, reference symbol P1 indicates a portion in contact with the active layer ORG of the pixel electrode PE included in the pixel PX1, and reference symbol P2 indicates a portion in contact with the active layer ORG of the pixel electrode PE included in the pixel PX2. Reference numeral P3 indicates a portion in contact with the active layer ORG of the pixel electrode PE included in the pixel PX3. Reference symbol L _A 1 indicates the dimension along the X direction of the contact portion P1, reference symbol L _A 2 indicates the dimension along the X direction of the contact portion P2, and reference symbol L _A 3 indicates the X direction of the contact portion P3. The dimension along is shown. Reference numeral L _B 1 indicates the dimension along the X direction of the light emitting layer EMT1, reference numeral L _B 2 indicates the dimension along the X direction of the light emitting layer EMT2, and reference numeral L _B 3 indicates the X direction of the light emitting layer EMT3. The dimension along is shown. Reference numeral D ₁₂ denotes the distance along the X direction between the contact portions P1 and P2, the reference numeral D ₂₃ denotes the distance along the X direction between the contact portions P2 and P3.

In the structure of FIG. 5, the dimensions L _A 1 to L _A 3 are equal to each other, the dimensions L _B 1 to L _B 3 are equal to each other, and the distances D ₁₂ and D ₂₃ are equal to each other. The difference between L _B 1-L _A 1 with dimension L _B 1 and dimensions L _A 1 is equal to the distance D _12, a difference L _B 2-L _A 2 between the dimension L _B 2 and dimensions L _A 2 is a distance D Equal to ₁₂ .

If this structure is employed, as shown in FIG. 6, is equal to parallel shift SFT in the X-direction position of the light-emitting layer EMT2 is D _12/2 or less, not face the light-emitting layer EMT2 the contact portion P2 region It does not occur. However, as shown in FIG. 7, when the shift SFT exceeds D _12/2, the region not facing the light-emitting layer EMT2 the contact portion P2 occurs. In this case, the organic EL element OLED of the pixel PX2 may not emit light.

  FIG. 8 is a plan view schematically showing an example of a state in which the relative positions of the light emitting layer and the pixel electrode are shifted in the structure of FIG.

In the structure of FIG. 3, the difference L _B 1-L _A 1 with dimension L _B 1 and dimensions L _A 1 is a distance D ₁₂ or less, the difference between the dimension L _B 2 and dimensions L _A 2 L _B 2-L _a 2 is greater than compared to the distance D _12. That is, the dimension L _A 1, the dimension L _B 1, the dimension L _A 2, the dimension L _B 2, and the distance D ₁₂ satisfy the relationship shown in the following inequalities (1) and (2).

L _B 1−L _A 1 ≦ D ₁₂ (1)
L _B 2−L _A 2> D ₁₂ (2)
When the structure of FIG. 3 is adopted, as shown in FIG. 8, if the deviation SFT is (L _B 2−L _A 2) / 2 or less, a region that does not face the light emitting layer EMT2 occurs in the contact portion P2. There is no. As is clear from inequality _{(2), (L B 2} -L A 2) / 2 is greater than D _12/2. That is, the structure of FIG. 3 is less likely to generate a region that does not face the light emitting layer EMT2 at the contact portion P2, as compared with the structure of FIG.

  In the structure of FIG. 8, the light emitting layer EMT1 and the light emitting layer EMT2 partially overlap above the contact part P1, but as described with reference to FIG. 4, the organic EL element including the light emitting layer EMT2 The OLED has a higher emission start voltage than the organic EL element OLED including the light emitting layer EMT1. That is, even if the light-emitting layer EMT1 and the light-emitting layer EMT2 partially overlap above the contact portion P1, the light-emitting layer EMT2 does not emit light at the overlapping portion if the applied voltage is sufficiently small. Therefore, color misregistration due to this overlap can be suppressed.

As in the case of the difference L _B 2 -L _A 2, if the difference L _B 1 -L _A 1 is made larger than D ₁₂ , even if the position of the light emitting layer EMT1 is greatly shifted in parallel to the X direction, the contact part P1 In this case, there is no region that does not face the light emitting layer EMT1. However, in this case, the following problems occur.

  FIG. 9 is a plan view schematically showing the arrangement of the light emitting layers of an organic EL display device according to another comparative example. FIG. 10 is a plan view schematically showing an example of a state in which the relative positions of the light emitting layer and the pixel electrode are shifted in the structure of FIG.

In the structure of FIG. 9, the difference L _B 1−L _A 1 is greater than D ₁₂ . Therefore, as shown in FIG. 10, even if the position of the light emitting layer EMT1 is largely shifted in parallel to the X direction, a region that does not face the light emitting layer EMT1 does not occur in the contact portion P1.

  However, as shown in FIG. 10, when the positional shift SFT of the light emitting layer EMT1 is large, the light emitting layer EMT1 and the light emitting layer EMT2 partially overlap above the contact portion P2. As described with reference to FIG. 4, the organic EL element OLED including the light emitting layer EMT1 has a lower emission start voltage than the organic EL element OLED including the light emitting layer EMT2. That is, when the light emitting layer EMT1 and the light emitting layer EMT2 partially overlap above the contact portion P2, the light emitting layer EMT1 emits light at the overlapping portion. Therefore, color misregistration due to this overlap occurs.

As is clear from the above, when the difference L _B 2−L _A 2 is larger than the difference L _B 1−L _A 1, the organic layer of the pixel PX2 is caused by the positional shift in the X direction of the light emitting layer EMT2. It is possible to suppress the EL element OLED from being unable to emit light. In addition, in this case, it is possible to suppress the occurrence of color shift in the organic EL elements OLED of the pixels PX1 and PX2 due to the positional shift in the X direction of the light emitting layers EMT1 and EMT2.

2 and 3, the dimension L _A 1 and the dimension L _A 2 are made equal to each other, and the dimension L _B 1 is made larger than the dimension L _B 2, whereby the difference L _B 2−L _A 2 is differentiated. It is larger than L _B 1-L _A 1. As described below with reference to FIGS. 11 to 13, the above-described effect is achieved by making the dimension L _B 1 and the dimension L _B 2 equal to each other and making the dimension L _A 2 smaller than the dimension L _A 1. Thus, the difference L _B 2−L _A 2 can be obtained even when the difference L _B 2−L _A 2 is larger than the difference L _B 1−L _A 1.

  FIG. 11 is a plan view schematically showing another example of the arrangement of the light emitting layers that can be employed in the display device of FIG. FIG. 12 is a plan view schematically showing an example of a state in which the relative positions of the light emitting layer and the pixel electrode are shifted in the structure of FIG. FIG. 13 is a plan view schematically showing another example of a state in which the relative position between the light emitting layer and the pixel electrode is shifted in the structure of FIG.

Also in the structure of FIG. 11, the dimension L _A 1, the dimension L _B 1, the dimension L _A 2, the dimension L _B 2, and the distance D ₁₂ are represented by inequalities (1) and (2), as in the structure of FIG. Satisfied relationship. Therefore, as shown in FIG. 12, even when the deviation SFT is relatively large, a region that does not face the light emitting layer EMT2 does not occur in the contact portion P2.

  In the state of FIG. 12, the light emitting layer EMT1 and the light emitting layer EMT2 partially overlap above the contact portion P1. However, as described with reference to FIG. 4, the organic EL element OLED including the light emitting layer EMT2 has a higher emission start voltage than the organic EL element OLED including the light emitting layer EMT1. Therefore, even if the light emitting layer EMT1 and the light emitting layer EMT2 partially overlap above the contact portion P1, the light emitting layer EMT2 does not emit light at the overlapping portion if the applied voltage is sufficiently small. Therefore, color misregistration due to this overlap can be suppressed.

  Further, in FIG. 13, the displacement SFT in the X direction of the position of the light emitting layer EMT1 is the maximum within a range where no region that does not face the light emitting layer EMT1 is generated in the contact portion P1. In this state, the light emitting layer EMT1 and the light emitting layer EMT2 do not overlap above the contact portion P2. Therefore, there is no color shift due to the overlap.

As is clear from the above, even when the dimension L _B 1 and the dimension L _B 2 are equal to each other and the dimension L _A 2 is smaller than the dimension L _A 1, the positional deviation of the light emitting layer EMT2 in the X direction is caused. This can prevent the organic EL element OLED of the pixel PX2 from being unable to emit light. In addition, in this case, it is possible to suppress the occurrence of color shift in the organic EL elements OLED of the pixels PX1 and PX2 due to the positional shift in the X direction of the light emitting layers EMT1 and EMT2.

  The design described above can also be applied to the pixels PX2 and PX3. This will be described with reference to FIGS.

  FIG. 14 is a plan view schematically showing still another example of the arrangement of the light emitting layers that can be employed in the display device of FIG. FIG. 15 is a plan view schematically showing an example of a state in which the relative positions of the light emitting layer and the pixel electrode are shifted in the structure of FIG. FIG. 16 is a plan view schematically showing another example of a state in which the relative positions of the light emitting layer and the pixel electrode are shifted in the structure of FIG. FIG. 17 is a plan view schematically showing still another example of a state in which the relative positions of the light emitting layer and the pixel electrode are shifted in the structure of FIG. FIG. 18 is a plan view schematically showing still another example of a state in which the relative position between the light emitting layer and the pixel electrode is shifted in the structure of FIG.

In the structure of FIG. 14 as well, the dimension L _A 1, the dimension L _B 1, the dimension L _A 2, the dimension L _B 2, and the distance D ₁₂ are represented by inequalities (1) and (2), as in the structure of FIG. Satisfied relationship. In addition to this, in the structure of FIG. 14, the dimension L _A 2, the dimension L _B 2, the dimension L _A 3, the dimension L _B 3, and the distance D ₂₃ satisfy the relationship shown by the inequalities (3) and (4). ing. In the case of achieving the relationship shown in inequality (1) to (4), as is clear from inequality (2) and (3), the distance D ₂₃ is longer as compared to the distance D _12.

L _B 2−L _A 2 ≦ D ₂₃ (3)
L _B 3 -L _A 3> D ₂₃ (4)
Therefore, as shown in FIGS. 15 and 17, even when the positional deviation SFT of the light emitting layer EMT2 is relatively large, a region that does not face the light emitting layer EMT2 does not occur in the contact portion P2. In addition, as shown in FIG. 18, even if the positional deviation SFT of the light emitting layer EMT3 is relatively large, a region that does not face the light emitting layer EMT3 does not occur in the contact portion P3.

  In the state of FIG. 15, the light emitting layer EMT1 and the light emitting layer EMT2 partially overlap above the contact portion P1. However, as described with reference to FIG. 4, the organic EL element OLED including the light emitting layer EMT2 has a higher emission start voltage than the organic EL element OLED including the light emitting layer EMT1. Therefore, even if the light emitting layer EMT1 and the light emitting layer EMT2 partially overlap above the contact portion P1, the light emitting layer EMT2 does not emit light at the overlapping portion if the applied voltage is sufficiently small. Therefore, color misregistration due to this overlap can be suppressed.

  In FIG. 16, the shift SFT in the X direction of the position of the light emitting layer EMT1 is the maximum within a range in which no region that does not face the light emitting layer EMT1 is generated in the contact portion P1. In this state, the light emitting layer EMT1 and the light emitting layer EMT2 do not overlap above the contact portion P2. Therefore, there is no color shift due to the overlap.

  In FIG. 17, the displacement SFT in the X direction of the position of the light emitting layer EMT2 is the maximum within a range in which a region that does not face the light emitting layer EMT2 is not generated in the contact portion P2. In this state, the light emitting layer EMT2 and the light emitting layer EMT3 do not overlap above the contact portion P3. Therefore, there is no color shift due to the overlap.

  In the state of FIG. 18, the light emitting layer EMT2 and the light emitting layer EMT3 partially overlap above the contact portion P2. However, as described with reference to FIG. 4, the organic EL element OLED including the light emitting layer EMT3 has a higher emission start voltage than the organic EL element OLED including the light emitting layer EMT2. Therefore, even if the light-emitting layer EMT2 and the light-emitting layer EMT3 partially overlap above the contact portion P2, the light-emitting layer EMT3 does not emit light at the overlapping portion if the applied voltage is sufficiently small. Therefore, color misregistration due to this overlap can be suppressed.

As is clear from the above, when the difference L _B 2−L _A 2 is larger than the difference L _B 1−L _A 1, the organic layer of the pixel PX2 is caused by the positional shift in the X direction of the light emitting layer EMT2. It is possible to suppress the EL element OLED from being unable to emit light. In addition, in this case, it is possible to suppress the occurrence of color shift in the organic EL elements OLED of the pixels PX1 and PX2 due to the positional shift in the X direction of the light emitting layers EMT1 and EMT2.

In addition, when the difference L _B 3 -L _A 3 is larger than the difference L _B 2 -L _A 2, the organic EL element OLED of the pixel PX3 emits light due to the positional shift in the X direction of the light emitting layer EMT3. It can be suppressed that it becomes impossible. In addition, in this case, it is possible to suppress the occurrence of color shift in the organic EL elements OLED of the pixels PX2 and PX3 due to the positional shift in the X direction of the light emitting layers EMT2 and EMT3.

The dimensions L _A 1 to L _A 3 may be equal to each other or may be different. The dimensions L _A 1 to L _A 3 may be determined based on, for example, luminous efficiency.

Each of the difference L _B 1 -L _A 1, the difference L _B 2 -L _A 2, and the difference L _B 3 -L _A 3 is, for example, in the range of 3 μm to 25 μm. When the difference is small, there is a possibility that the organic EL element OLED cannot emit light only by slightly shifting the position of the light emitting layer. If the difference is large, the aperture ratio may decrease, or high positional accuracy may be required to prevent color misregistration.

  In this embodiment, the present invention is applied to a bottom emission type organic EL display device, but the present invention is also applicable to a top emission type organic EL display device. Further, in this aspect, the configuration in which the current signal is written as the video signal in the pixel circuit is adopted, but the configuration in which the voltage signal is written in the pixel circuit as the video signal may be employed.

1 is a plan view schematically showing a display device according to one embodiment of the present invention. FIG. 2 is a cross-sectional view schematically illustrating an example of a structure that can be employed in the display device of FIG. 1. The top view which shows roughly an example of arrangement | positioning of the light emitting layer employable as the display apparatus of FIG. The graph which shows the example of the voltage luminance characteristic of an organic EL element. The top view which shows roughly arrangement | positioning of the light emitting layer of the organic electroluminescence display which concerns on one comparative example. FIG. 6 is a plan view schematically showing an example of a state in which the relative positions of the light emitting layer and the pixel electrode are shifted in the structure of FIG. 5. FIG. 6 is a plan view schematically showing another example of the state where the relative positions of the light emitting layer and the pixel electrode are shifted in the structure of FIG. 5. FIG. 4 is a plan view schematically showing an example of a state in which the relative positions of the light emitting layer and the pixel electrode are shifted in the structure of FIG. 3. The top view which shows roughly arrangement | positioning of the light emitting layer of the organic electroluminescence display which concerns on another comparative example. FIG. 10 is a plan view schematically showing an example of a state in which the relative positions of the light emitting layer and the pixel electrode are shifted in the structure of FIG. 9. The top view which shows schematically the other example of arrangement | positioning of the light emitting layer employable for the display apparatus of FIG. FIG. 12 is a plan view schematically showing an example of a state where the relative positions of the light emitting layer and the pixel electrode are shifted in the structure of FIG. 11. FIG. 12 is a plan view schematically showing another example of a state in which the relative positions of the light emitting layer and the pixel electrode are shifted in the structure of FIG. 11. The top view which shows schematically the further another example of arrangement | positioning of the light emitting layer employable as the display apparatus of FIG. FIG. 15 is a plan view schematically showing an example of a state in which the relative positions of the light emitting layer and the pixel electrode are shifted in the structure of FIG. 14. FIG. 15 is a plan view schematically showing another example of a state in which the relative position between the light emitting layer and the pixel electrode is shifted in the structure of FIG. 14. FIG. 15 is a plan view schematically showing still another example of a state in which the relative position between the light emitting layer and the pixel electrode is shifted in the structure of FIG. 14. FIG. 15 is a plan view schematically showing still another example of a state in which the relative position between the light emitting layer and the pixel electrode is shifted in the structure of FIG. 14.

Explanation of symbols

  C ... capacitor, CE ... counter electrode, DE ... drain electrode, DL ... video signal line, DP ... display panel, DR ... drive transistor, EMT1 ... light emitting layer, EMT2 ... light emitting layer, EMT3 ... light emitting layer, G ... gate, GI DESCRIPTION OF SYMBOLS ... Gate insulating film, II ... Interlayer insulating film, ND1 ... Power supply terminal, ND1 '... Constant potential terminal, ND2 ... Power supply terminal, OLED ... Organic EL element, ORG ... Organic substance layer, PE ... Pixel electrode, PI ... Partition insulating layer, PS ... Passivation film, PSL ... Power supply line, PX1 ... Pixel, PX2 ... Pixel, PX3 ... Pixel, SC ... Semiconductor layer, SE ... Source electrode, SFT ... Shift, SL1 ... Scanning signal line, SL2 ... Scanning signal line, SUB ... Insulating substrate, SWa ... Switching transistor, SWb ... Switching transistor, SWc ... Switching transistor, TPL ... Region, UC ... Ann Bar coating layer, VL1 ... curve, VL2 ... curve, VL3 ... curve, XDR ... video signal line driver, YDR ... scanning signal line driver.

Claims (8)

Insulating substrate, adjacent to each other, each pixel electrode disposed on said insulating substrate, counter electrode facing this, and active layer interposed between them and including a light emitting layer And first and second organic EL elements comprising:
The first organic EL element is different from the second organic EL element in the emission color of the light emitting layer, and emits light at a voltage lower than that of the second organic EL element.
The dimension L _B 1 along the arrangement direction of the first and second organic EL elements of the light emitting layer included in the first organic EL element and the active layer of the pixel electrode included in the first organic EL element are in contact with each other. The difference L _B 1 -L _A 1 between the first portion and the dimension L _A 1 along the arrangement direction is a dimension L _B 2 along the arrangement direction of the light emitting layer included in the second organic EL element. And the difference L _B 2−L _A 2 between the second portion in contact with the active layer of the pixel electrode included in the second organic EL element and the dimension L _A 2 along the arrangement direction. An organic EL display device characterized by being small. The difference L _B 1 -L _A 1 is not more than a distance D ₁₂ along the arrangement direction between the first and second parts, and the difference L _B 2 -L _A 2 is compared with the distance D _12. The organic EL display device according to claim 1, wherein the organic EL display device is larger. The organic EL display device according to claim 1, wherein the dimension L _B 2 is larger than the dimension L _B 1. The organic EL display device according to claim 1, wherein the dimension L _A 2 is smaller than the dimension L _A 1. 2. The organic EL display device according to claim 1, wherein the dimension L _B 2 is larger than the dimension L _B 1 and the dimension L _A 2 is smaller than the dimension L _A 1. . Insulating substrate, adjacent to each other, each pixel electrode disposed on said insulating substrate, counter electrode facing this, and active layer interposed between them and including a light emitting layer And first to third organic EL elements including:
The first organic EL element is adjacent to the third organic EL element across the second organic EL element,
The first to third organic EL elements have different emission colors of the light emitting layer,
The first organic EL element emits light at a voltage lower than that of the second organic EL element, the second organic EL element emits light at a voltage lower than that of the third organic EL element,
The dimension L _B 1 along the arrangement direction of the first and second organic EL elements of the light emitting layer included in the first organic EL element and the active layer of the pixel electrode included in the first organic EL element are in contact with each other. The difference L _B 1 -L _A 1 between the first portion and the dimension L _A 1 along the arrangement direction is a dimension L _B 2 along the arrangement direction of the light emitting layer included in the second organic EL element. And the difference L _B 2−L _A 2 between the second portion in contact with the active layer of the pixel electrode included in the second organic EL element and the dimension L _A 2 along the arrangement direction. small,
The difference L _B 2−L _A 2 is the dimension L _B 3 along the arrangement direction of the light emitting layer included in the third organic EL element and the active layer of the pixel electrode included in the third organic EL element. the organic EL display device, characterized in that smaller compared to the difference L _B 3-L _a 3 with dimensions L _a 3 along the arrangement direction of the third portion in contact. The difference L _B 1 -L _A 1 is not more than a distance D ₁₂ along the arrangement direction between the first and second parts, and the difference L _B 2 -L _A 2 is compared with the distance D _12. The difference L _B 2−L _A 2 is less than or equal to the distance D ₂₃ along the arrangement direction between the second and third portions, and the difference L _B 3−L _A 3 is less than the distance D ₂₃ . The organic EL display device according to claim 6, wherein the organic EL display device is larger in comparison. Claims wherein the distance D ₁₂ is along the arrangement direction between the first and second portions, as compared to the distance D ₂₃ along the arrangement direction between the second and third portions, wherein the shorter Item 2. An organic EL display device according to Item 1.

Images