JP2006100186A - Organic el display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent occurrence of display unevenness of stripe shape which can be visible in the display picture when hollow sealing is carried out in an EL display device of an upper side emission type. <P>SOLUTION: The organic EL display device 1 is of the upper side emission type and is equipped with an array substrate 2 having an insulating substrate 10 and a plurality of organic EL elements 40 arranged on its one main surface and a sealing substrate 3 which faces the plurality of organic EL elements 40 and are separated away from the organic EL elements 40. The spacing between the array substrate 2 and the sealing substrate 3 is either filled with a material having a refractive index smaller than that of the front electrode 43 of the organic EL element 40 or vacuum, and the variation Δd in the distance d from the organic EL element 40 to the sealing substrate 3 and the refractive index Δn of the spacing between the array substrate 2 and the sealing substrate 3 satisfy a relation as shown in the inequality: n×Δd≤1 μm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

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

  An organic EL element easily deteriorates when it comes into contact with moisture or oxygen. Therefore, in the organic EL display device, the organic EL element is sealed to prevent contact between the organic EL element and moisture or oxygen.

  As a sealing method of the organic EL element, there are hollow sealing and thin film sealing. In the hollow sealing, for example, a sealing substrate such as glass is disposed so as to face the surface of the array substrate on which the organic EL element is formed and to be separated from the array substrate. And the opposing surface peripheral parts of these board | substrates are bonded together with an adhesive agent, and a hollow body is formed. The internal space of the hollow body is filled with an inert gas or is evacuated, for example. In this case, typically, a bottom emission type is adopted for the organic EL display device, and a desiccant is further disposed in the inner space.

  As described above, when hollow sealing is performed, it is common to adopt a bottom emission type for an organic EL display device. On the contrary, the present inventors performed the above-described hollow sealing with a top emission type organic EL display device. As a result, the present inventors have found that striped display unevenness may occur in a display image when hollow sealing is performed with a top emission type organic EL display device.

  An object of the present invention is to prevent striped display unevenness that can be visually recognized in a display image when hollow sealing is performed in a top emission type organic EL display device.

  According to a first aspect of the present invention, an array substrate comprising an insulating substrate and a plurality of organic EL elements arranged on one main surface thereof, and a seal facing the plurality of organic EL elements and spaced apart from the organic EL elements. A space between the array substrate and the sealing substrate is filled with a material having a refractive index smaller than that of the front electrode of the organic EL element or is a vacuum, The variation Δd of the distance d from the organic EL element to the sealing substrate and the refractive index n of the space between the array substrate and the sealing substrate satisfy the relationship represented by the inequality: n × Δd ≦ 1 μm. Thus, a top emission type organic EL display device is provided.

  According to the second aspect of the present invention, an array substrate comprising an insulating substrate and a plurality of organic EL elements arranged on one main surface thereof, and a seal facing the plurality of organic EL elements and spaced apart from the organic EL elements. A space between the array substrate and the sealing substrate is filled with a material having a refractive index smaller than that of the front electrode of the organic EL element or is a vacuum, The distance d from the organic EL element to the sealing substrate and the refractive index n of the space between the array substrate and the sealing substrate satisfy the relationship shown by the inequality: n × d ≧ 20 μm. A top emission organic EL display device is provided.

  According to the third aspect of the present invention, an array substrate comprising an insulating substrate and a plurality of organic EL elements arranged on one main surface thereof, and a seal facing the plurality of organic EL elements and spaced apart from the organic EL elements. A space between the array substrate and the sealing substrate is filled with a material having a refractive index smaller than that of the front electrode of the organic EL element or is a vacuum, Of the surface of the sealing substrate facing the array substrate, the center of the first region facing the plurality of organic EL elements is recessed with respect to the second region in contact with the adhesive layer, In the vicinity of the boundary between the first region and the second region, the surface of the sealing substrate that faces the array substrate is inclined with respect to the main surface of the insulating substrate. The gradient δd / δL and the array base The top emission organic EL display characterized in that the refractive index n of the space between the plate and the sealing substrate satisfies the relationship shown by the inequality: n × δd / δL ≧ 1/2000 An apparatus is provided.

  According to the present invention, when hollow sealing is performed with a top emission type organic EL display device, it is possible to prevent the occurrence of striped display unevenness that can be visually recognized in a display image.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same reference numerals are given to components that exhibit the same or similar functions, and duplicate descriptions are omitted.

  FIG. 1 is a cross-sectional view schematically showing an organic EL display device according to the first embodiment of the present invention. FIG. 2 is a partial cross-sectional view showing the organic EL display device of FIG. 1 in an enlarged manner. In FIGS. 1 and 2, the organic EL display device is drawn so that its display surface, that is, the front surface or the light emitting surface faces upward, and the back surface faces downward.

  An organic EL display device 1 shown in FIG. 1 is a top emission type organic EL display device that employs an active matrix driving method. The organic EL display device 1 includes an array substrate 2 and a sealing substrate 3.

  The array substrate 2 and the sealing substrate 3 are disposed so as to face each other. An adhesive layer 4 is interposed between the peripheral portions of the opposing surfaces of the array substrate 2 and the sealing substrate 3. The adhesive layer 4 has a frame shape, and forms an airtight space between the array substrate 2 and the sealing substrate 3. This hermetic space is filled with an inert gas such as nitrogen gas or is in a vacuum.

  Instead of using the adhesive layer 4, a frit seal or the like may be used for bonding the array substrate 2 and the sealing substrate 3. Further, the space between the array substrate 2 and the sealing substrate 3 may be filled with a low refractive index material such as a transparent resin.

  The array substrate 2 includes an insulating substrate 10 such as a glass substrate. On the insulating substrate 10, a plurality of pixels are arranged in a matrix.

  Each pixel includes a pixel circuit and an organic EL element 40. The pixel circuit includes, for example, a drive control element (not shown) and an output control switch 20 connected in series with the organic EL element 40 between a pair of power supply terminals, and a pixel switch (not shown). The drive control element has a control terminal connected to a video signal line (not shown) via a pixel switch, and outputs a current having a magnitude corresponding to the video signal supplied from the video signal line to the output control switch 20. To the organic EL element 40. The control terminal of the pixel switch is connected to a scanning signal line (not shown), and the switching operation is controlled by the scanning signal supplied from the scanning signal line. Note that other structures may be employed for these pixels.

On the substrate 10, for example, a SiN _x layer and a SiO _x layer are sequentially stacked as the undercoat layer 12. On the undercoat layer 12, for example, a semiconductor layer 13, which is a polysilicon layer in which a channel and source / drain are formed, a gate insulating film 14 that can be formed using, for example, TEOS (TetraEthyl OrthoSilicate), etc., and MoW, for example, The gate electrodes 15 are sequentially stacked, and they constitute a top gate type thin film transistor (hereinafter referred to as TFT). In this example, these TFTs are used as pixel switches, output control switches 20, and drive control element TFTs. A scanning signal line (not shown) that can be formed in the same process as the gate electrode 15 is further disposed on the gate insulating film 14.

The gate insulating film 14 and the gate electrode 15 are covered with an interlayer insulating film 17 made of, for example, SiO _x formed by a plasma CVD method or the like. A source / drain electrode 21 is disposed on the interlayer insulating film 17 and is buried with a passivation film 18 made of, for example, SiN _x . The source / drain electrode 21 has, for example, a three-layer structure of Mo / Al / Mo, and is electrically connected to the source / drain of the TFT through a contact hole provided in the interlayer insulating film 17. . Further, video signal lines (not shown) that can be formed in the same process as the source / drain electrodes 21 are further arranged on the interlayer insulating film 17.

  A planarization layer 19 is formed on the passivation film 18. A reflective layer 70 is disposed on the planarization layer 19. As a material for the planarization layer 19, for example, a hard resin can be used. As a material of the reflective layer 70, for example, a metal material such as Al can be used.

  The planarizing layer 19 and the reflective layer 70 are covered with the light extraction layer 30. The light extraction layer 30 is not necessarily provided. However, when the light extraction layer 30 is provided, the traveling direction of light propagating in the film surface direction can be changed while repeating reflection inside the organic EL element 40. This makes it possible to extract light emitted from the light emitting layer of the organic EL element 40 to the outside of the organic EL element 40 with high efficiency. As the light extraction layer 30, for example, a light scattering layer or a diffraction grating can be used.

  On the light extraction layer 30, light transmissive first electrodes 41 are juxtaposed apart from each other as a back electrode. Each first electrode 41 is disposed to face the reflective layer 70. In addition, each first electrode 41 is connected to the drain electrode 21 through a through hole provided in the passivation film 18, the planarization layer 19, and the light extraction layer 30.

  The first electrode 41 is an anode in this example. As a material of the first electrode 41, for example, a transparent conductive oxide such as ITO (Indium Tin Oxide) can be used.

  A partition insulating layer 50 is further disposed on the light extraction layer 30. The partition insulating layer 50 is provided with a through hole at a position corresponding to the first electrode 41. The partition insulating layer 50 is an organic insulating layer, for example, and can be formed using a photolithography technique.

  An organic layer 42 including a light emitting layer is disposed on the first electrode 41 exposed in the through hole of the partition insulating layer 50. The light emitting layer is, for example, a thin film containing a luminescent organic compound whose emission color is red, green, or blue. The organic layer 42 can further include layers other than the light emitting layer. For example, the organic layer 42 may further include a buffer layer that plays a role in mediating injection of holes from the first electrode 41 to the light emitting layer. In addition, the organic layer 42 may further include a hole transport layer, a hole blocking layer, an electron transport layer, an electron injection layer, and the like.

  The partition insulating layer 50 and the organic layer 42 are covered with a light transmissive second electrode 43 that is a front electrode. In this example, the second electrode 43 is a cathode provided continuously in common with each pixel. The second electrode 43 is formed on the same layer as the video signal line through a contact hole (not shown) provided in the passivation film 18, the planarizing layer 19, the light extraction layer 30, and the partition insulating layer 50. The electrode wiring is electrically connected. Each organic EL element 40 includes the first electrode 41, the organic material layer 42, and the second electrode 43.

  As described above, when hollow sealing is performed with a top emission type organic EL display device, striped display unevenness that may be visually recognized in a display image may occur. As a result of detailed investigations on this, the present inventors have found that the striped display unevenness is an interference fringe resulting from a variation in the distance between the array substrate 2 and the sealing substrate 3.

In this embodiment, the variation Δd (3σ) of the distance d from the organic EL element 40 to the sealing substrate 3 and the refractive index n of the space between the array substrate 2 and the sealing substrate 3 are expressed by the following inequality ( It is determined so as to satisfy the relationship shown in 1).
n × Δd ≦ 1 μm (1)
In this way, it is possible to prevent the occurrence of interference fringes themselves or to sufficiently widen the intervals between the fringes of the interference fringes, and thus to prevent the striped display unevenness from being visually recognized in the display image. Become.

  In this way, in order to prevent the striped display unevenness from being visually recognized in the display image, the variation Δd may be reduced. The variation Δd can be reduced, for example, by adopting the following structure.

  FIG. 3 is a cross-sectional view schematically showing an example of a structure that can be employed in the organic EL display device according to the first aspect of the present invention. FIG. 4 is a partial sectional view showing the structure of FIG. 3 in an enlarged manner. 3 and 4, the organic EL display device is depicted such that its display surface, that is, the front surface or the light emitting surface, faces upward, and the back surface faces downward.

  In the structure shown in FIGS. 3 and 4, the array substrate 2 and the sealing substrate 3 are in contact with each other at a position corresponding to the upper surface of the partition insulating layer 50. In this way, the variation Δd can be reduced, and therefore it is possible to prevent the striped display unevenness from being visually recognized in the display image.

In this structure, of the surface of the sealing substrate 3 facing the array substrate 2, the first region facing the organic EL element 40 is raised with respect to the second region in contact with the adhesive layer 4. is doing. Here, as an example, the sealing substrate 3 in which the light transmission layer 90 is disposed on the transparent substrate 80 is used. The light transmission layer 90 covers only the substantially central portion of the surface of the transparent substrate 80 facing the array substrate 2. The transparent substrate 80 is a glass substrate, for example, and the light transmission layer 90 is a layer having a refractive index substantially equal to or smaller than that of the transparent substrate 80 such as a SiO ₂ layer.

Such a sealing substrate 3 is advantageous in the following points.
When the opposing surface of the sealing substrate 3 to the array substrate 2 is flat, the adhesive layer 4 must be very thin in order to bring the opposing surfaces of the array substrate 2 and the sealing substrate 3 into contact with each other. However, if the pressure applied to the substrate when the array substrate 2 and the sealing substrate 3 are bonded together in order to make the adhesive layer 4 thin, the width of the adhesive layer 4 tends to be uneven.

  In the structure of FIGS. 3 and 4, the first region of the surface of the sealing substrate 3 facing the array substrate 2 facing the organic EL element 40 is in contact with the adhesive layer 4 as described above. Raised with respect to the second region. Therefore, even if the adhesive layer 4 is not thinned, the opposing surfaces of the array substrate 2 and the sealing substrate 3 can be brought into contact with each other, and therefore, the width of the adhesive layer 4 can be prevented from becoming uneven. it can.

Next, the second aspect of the present invention will be described.
FIG. 5 is a cross-sectional view schematically showing an organic EL display device according to the second embodiment of the present invention.

In this aspect, the distance d and the refractive index n described in the first aspect satisfy the relationship represented by the following inequality (2) in order to prevent the striped display unevenness from being visually recognized in the display image. Determine to do.
n × d ≧ 20 μm (2)
That is, the distance d is made sufficiently long. Other than this, the second aspect is the same as the first aspect.

  Increasing the distance d decreases the contrast of the interference fringes. Therefore, if the distance d is made sufficiently short, it is possible to prevent the striped display unevenness from being visually recognized in the display image.

  The distance d may be about 100 μm or less, for example. When the distance d is long, the organic EL display device 1 becomes thick and its manufacture becomes difficult.

  By the way, when the surface of the sealing substrate 3 facing the array substrate 2 is flat, the adhesive layer 4 has to be thickened corresponding to the increase in the distance d. In this case, accurate control of the distance d may be difficult.

  6 to 8 are cross-sectional views schematically showing examples of structures that can be employed in the organic EL display device according to the second aspect of the present invention. In FIG. 6 to FIG. 8, components interposed between the insulating substrate 10 and the first electrode 41 are omitted.

  6 to 8, a spacer 100 is disposed between the array substrate 2 and the sealing substrate 3. More specifically, the spacer 100 is disposed between the array substrate 2 and the sealing substrate 3 at a position corresponding to the upper surface of the partition insulating layer 50. The pressure in the space between the array substrate 2 and the sealing substrate 3 is smaller than the pressure outside the organic EL display device 1, for example, atmospheric pressure. By adopting such a structure, even if the distance d is increased, the variation Δd can be reduced.

  In the structure of FIG. 6, granular spacers are used as the spacers 100, and these spacers 100 are bonded to the surface of the sealing substrate 3 facing the array substrate 2 by an adhesive 110. For adhesion of the spacer 100 to the sealing substrate 3, for example, the granular spacer 100 surface-treated with the adhesive 110 is dispersed on the sealing substrate 3, and a coating liquid containing the adhesive 110 and the granular spacer 100 is used. Can be applied to the sealing substrate, the adhesive 110 can be formed as a thin film on the sealing substrate 3, and the granular spacers 100 can be dispersed on the adhesive 110. In addition, as a material of these granular spacer 100 and the adhesive agent 100, a transparent material is typically used.

  In the structure of FIG. 7, a columnar spacer is used as the spacer 100. In addition, in the structure of FIG. 7, these spacers 100 are formed on the surface of the sealing substrate 3 facing the array substrate 2 by using, for example, a photolithography technique. When the columnar spacer 100 is formed on the sealing substrate 3, the high columnar spacer 100 can be formed relatively easily.

  In the structure of FIG. 8, a columnar spacer is used as the spacer 100 as in the structure of FIG. 7. However, in the structure of FIG. 8, these spacers 100 are formed on the surface of the array substrate 2 facing the sealing substrate 3 by using, for example, a photolithography technique. When the columnar spacer 100 is formed on the array substrate 2, high positional accuracy is not required for bonding the array substrate 2 to the sealing substrate 3.

Next, the third aspect of the present invention will be described.
FIG. 9 is a cross-sectional view schematically showing an organic EL display device according to the third aspect of the present invention.

In this aspect, as shown in FIG. 9, the center of the first region A1 facing the organic EL element 40 in the surface facing the array substrate 2 of the sealing substrate 3 is in contact with the adhesive layer 4. The second region A2 is recessed. In addition, in this aspect, in the vicinity of the boundary between the first region A1 and the second region A2, the surface of the sealing substrate 3 facing the array substrate 2 is inclined with respect to the main surface of the insulating substrate 10, and this inclined portion At least in part, the gradient δd / δL and the refractive index n of the space between the array substrate 2 and the sealing substrate 3 are determined so that they satisfy the relationship represented by the following inequality (3).
n × δd / δL ≧ 1/2000 (3)
Except for this, the third aspect is the same as the first aspect.

  When the gradient δd / δL is large, the fringe width and interval of the interference fringes generated near the boundary between the first region A1 and the second region A2 are reduced. If the gradient δd / δL is sufficiently large, the width and interval of the interference fringes can be made so narrow that individual fringes cannot be identified. Therefore, it is possible to prevent the striped display unevenness from being visually recognized in the display image.

  The maximum value of the gradient δd / δL may be about 1/100 or less, for example. When the gradient δd / δL is increased, the glass strength and the seal strength may be insufficient.

  In this aspect, at the position corresponding to the central portion of the first region A1, the distance d and the refractive index n are similar to those described in the second aspect, as shown by the inequality: n × d ≧ 20 μm. It may be determined to satisfy In this way, it is possible to prevent the striped display unevenness from being visually recognized in the display image at a position corresponding to the central portion of the first area A1.

  In this aspect, in order to dent the center of the first area A1 with respect to the second area A2, for example, the spacer 100 described in the second aspect may be used. That is, the spacer 100 is disposed only at a position between the array substrate 2 and the sealing substrate 3 and corresponding to the center of the first region A1. In addition, the adhesive layer 4 is made sufficiently thin. In this way, as shown in FIG. 9, the center of the first area A1 can be recessed with respect to the second area A2.

Next, tests related to the above inequalities (1) to (3) will be described.
First, a plurality of organic EL display devices 1 were produced. Here, the diagonal dimension of each organic EL display device 1 is 5 inches, a glass substrate is used as the sealing substrate 3, and the space between the array substrate 2 and the sealing substrate 3 is vacuum. Hereinafter, these organic EL display devices 1 are referred to as samples (A) to (I).

  In the samples (A) to (D) and (F) to (I), for example, as shown in FIGS. 1 and 5, the sealing substrate 3 was not bent and remained substantially flat. On the other hand, the sample (E) bent the sealing substrate 3, for example, as shown in FIG.

  Next, images were displayed with these samples (A) to (I), and it was examined by visual inspection whether or not striped display unevenness that could be visually recognized in the display image occurred. Further, these samples (A) to (I) were irradiated with light from the sealing substrate 3 side by a surface inspection lamp, and it was investigated whether or not interference fringes that could be visually recognized were generated.

These results and the variations Δd, distances d and gradients δd / δL of samples (A) to (I) are summarized in the following table.

  In the table above, the symbols “◯”, “△”, and “×” described in the “Display unevenness” and “Interference fringe” columns indicate that no display unevenness or interference fringe was observed at all. It is shown that display unevenness or interference fringes are visually recognized only when observed, and that clear display unevenness or interference fringes are visually recognized. In the column of sample (E), various data are described in two lines. In the first row, data relating to the position corresponding to the center of the first area A1 shown in FIG. 9 is described, and in the second line, in the vicinity of the boundary between the first area A1 and the second area A2. The data about the corresponding position is described.

  As shown in the above table, samples (A), (B), (F) and (H) having a variation Δd of about 1 μm or less, and samples (H) and (I) having a distance d of about 20 μm or more. Then, the striped display nonuniformity which can be visually recognized in a display image did not arise. In sample (E), striped display unevenness was visually recognized in the display image in the region where the gradient δd / δL was less than 1 / 50,000, but in the region where the gradient δd / δL was 1/2000 or more, the display image There was no striped display unevenness that could be visually recognized inside.

1 is a cross-sectional view schematically showing an organic EL display device according to a first embodiment of the present invention. FIG. 2 is a partial cross-sectional view showing the organic EL display device of FIG. 1 in an enlarged manner. 1 is a cross-sectional view schematically showing an example of a structure that can be employed in an organic EL display device according to a first aspect of the present invention. The fragmentary sectional view which expands and shows the structure of FIG. Sectional drawing which shows schematically the organic electroluminescence display which concerns on the 2nd aspect of this invention. Sectional drawing which shows schematically the example of the structure employable with the organic electroluminescence display which concerns on the 2nd aspect of this invention. Sectional drawing which shows schematically the example of the structure employable with the organic electroluminescence display which concerns on the 2nd aspect of this invention. Sectional drawing which shows schematically the example of the structure employable with the organic electroluminescence display which concerns on the 2nd aspect of this invention. Sectional drawing which shows schematically the organic electroluminescence display which concerns on the 3rd aspect of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Organic EL display device, 2 ... Array substrate, 3 ... Sealing substrate, 4 ... Adhesive layer, 10 ... Insulating substrate, 12 ... Undercoat layer, 13 ... Semiconductor layer, 14 ... Gate insulating film, 15 ... Gate electrode , 17 ... Interlayer insulating film, 18 ... Passivation film, 19 ... Planarization layer, 20 ... Output control switch, 21 ... Source / drain electrode, 30 ... Light extraction layer, 40 ... Organic EL element, 41 ... First electrode, 42 DESCRIPTION OF SYMBOLS ... Organic substance layer, 43 ... 2nd electrode, 50 ... Partition insulating layer, 70 ... Reflective layer, 80 ... Transparent substrate, 90 ... Light transmission layer, 100 ... Spacer, 110 ... Adhesive.

Claims (14)

An array substrate comprising an insulating substrate and a plurality of organic EL elements arranged on one main surface thereof;
A sealing substrate facing the plurality of organic EL elements and spaced apart from the organic EL elements;
The space between the array substrate and the sealing substrate is filled with a material having a refractive index smaller than that of the front electrode of the organic EL element or is vacuum, and the sealing is performed from the organic EL element. The variation Δd of the distance d to the substrate and the refractive index n of the space between the array substrate and the sealing substrate satisfy the relationship represented by the inequality: n × Δd ≦ 1 μm. A top emission type organic EL display device.   The array substrate further includes a partition insulating layer interposed between the plurality of organic EL elements, and the array substrate and the sealing substrate are in contact with each other at a position corresponding to an upper surface of the partition insulating layer. The organic EL display device according to claim 1.   A frame-shaped adhesive layer disposed between the array substrate and the sealing substrate and surrounding the plurality of organic EL elements; and a surface of the sealing substrate facing the array substrate The organic EL according to claim 1, wherein the first region facing the plurality of organic EL elements is raised with respect to the second region in contact with the adhesive layer. Display device. An array substrate comprising an insulating substrate and a plurality of organic EL elements arranged on one main surface thereof;
A sealing substrate facing the plurality of organic EL elements and spaced apart from the organic EL elements;
The space between the array substrate and the sealing substrate is filled with a material having a refractive index smaller than that of the front electrode of the organic EL element or is vacuum, and the sealing is performed from the organic EL element. The distance d to the substrate and the refractive index n of the space between the array substrate and the sealing substrate satisfy the relationship represented by the inequality: n × d ≧ 20 μm. Type organic EL display.   The spacer further includes a spacer between the array substrate and the sealing substrate, and the array substrate further includes a partition insulating layer interposed between the plurality of organic EL elements. The organic EL display device described in 1. An array substrate comprising an insulating substrate and a plurality of organic EL elements arranged on one main surface thereof;
A sealing substrate facing the plurality of organic EL elements and spaced apart from the organic EL elements;
The space between the array substrate and the sealing substrate is filled with a material having a refractive index smaller than that of the front electrode of the organic EL element or is vacuum, and the array substrate of the sealing substrate The center of the first region facing the plurality of organic EL elements is recessed with respect to the second region in contact with the adhesive layer, and the first region of the first region In the vicinity of the boundary with the two regions, the surface of the sealing substrate facing the array substrate is inclined with respect to the main surface of the insulating substrate, and at least part of the inclined portion has a gradient δd / δL, The top emission organic EL, wherein the refractive index n of the space between the array substrate and the sealing substrate satisfies the relationship represented by the inequality: n × δd / δL ≧ 1/2000 Display device.   The organic EL display device according to claim 1, further comprising a spacer at a position between the array substrate and the sealing substrate and corresponding to a center of the first region.   The organic EL display device according to claim 7, wherein the array substrate further includes a partition insulating layer interposed between the plurality of organic EL elements.   The distance d from the organic EL element to the sealing substrate at the position corresponding to the center of the first region and the refractive index n satisfy the relationship represented by the inequality: n × d ≧ 20 μm. The organic EL display device according to claim 6.   The organic EL display device according to claim 7, wherein the spacer is a granular spacer supported on a surface of the sealing substrate facing the array substrate.   The organic EL display device according to claim 7, wherein the spacer is a columnar spacer formed on a surface of the sealing substrate facing the array substrate.   The organic EL display device according to claim 8, wherein the spacer is a columnar spacer formed on the partition insulating layer.   The organic EL display device according to claim 1, wherein the space is filled with an inert gas.   14. The array substrate according to claim 1, further comprising a light extraction layer disposed between the insulating substrate and the sealing substrate and facing the plurality of organic EL elements. 2. The organic EL display device according to item 1.

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